Specimen Type

Specimen Adequacy

General Categorization (Optional)

Interpretation/Result

Adjunctive Testing

Computer-Assisted Interpretation of Cervical Cytology

Educational Notes and Comments Appended to Cytology Reports (Optional)

Adequacy

Endocervical/Transformation Zone Component (Figs. 1.1 and 1.2)

Fig. 1.1.

Satisfactory for evaluation . Endocervical/transformation zone component present. Normal endocervical cells. LBC liquid-based cytology preparation.

Fig. 1.2.

Satisfactory for evaluation. Endocervical/transformation zone component present. Immature and mature metaplastic cells. CP conventional preparation.

Unsatisfactory Specimen (Fig. 1.3)

Fig. 1.3.

Unsatisfactory for evaluation, obscuring exudate. The specimen is totally obscured by acute inflammatory cells precluding evaluation. Greater than 75% obscuring is considered unsatisfactory if no abnormal cells are identified. CP conventional preparation.

Trichomonas vaginalis (Fig. 1.4)

Fig. 1.4.

Trichomonas vaginalis . Pear-shaped organisms with eccentrically located nucleus and granular cytoplasm. LBC liquid-based cytology preparation.

Fungal Organisms Morphologically Consistent with Candida Species (Fig. 1.5)

Fig. 1.5.

Fungal organisms morphologically consistent with Candida species. Pseudohyphae and yeast forms are present. LBC liquid-based cytology preparation.

Shift in Flora Suggestive of Bacterial Vaginosis (Fig. 1.6)

Fig. 1.6.

Shift in flora suggestive of bacterial vaginosis. Clue cells with coccobacilli covering the cytoplasm are present. LBC liquid-based cytology preparation.

Bacteria Morphologically Consistent with Actinomyces (Fig. 1.7)

Fig. 1.7.

Bacteria morphologically consistent with Actinomyces species. A cluster of thin filamentous bacilli are present. LBC liquid-based cytology preparation.

Cellular Changes Consistent with Herpes Simplex Virus (Fig. 1.8)

Fig. 1.8.

Cellular changes consistent with herpes simplex virus . Multinucleated giant cell with molding, ground-glass nuclei, and intranuclear inclusions LBC liquid-based cytology preparation.

Chlamydia trachomatis

Lactobacillus acidophilus (Döderlein Bacilli)

Leptothrix

Molluscum Contagiosum (Pox Virus)

Enterobius vermicularis (Pinworm)

Entamoeba histolytica

Cytomegalovirus (CMV)

Typical Repair (Figs. 1.13 and 1.14)

Fig. 1.13.

Reactive cellular changes associated with inflammation. Sheet of squamous cells with distinct borders, abundant cytoplasm, enlarged uniformly round nuclei, and nucleoli. Isolated atypical cells are not observed. CP conventional preparation.

Fig. 1.14.

Reactive cellular changes . Flat sheet of squamous cells with slightly enlarged uniform nuclei, abundant cytoplasm, and nucleoli. Polymorphonuclear leukocytes are present in the background. LBC liquid-based cytology preparation.

Radiation Effect (Figs. 1.15 and 1.16)

Fig. 1.15.

Reactive cellular changes associated with radiation effect. Large intermediate and metaplastic cells with enlarged nuclei and abundant cytoplasm. Note the cytoplasmic polychromatic staining and vacuolization. LBC liquid-based cytology preparation.

Fig. 1.16.

Reactive cellular changes associated with radiation effect. LBC liquid-based cytology preparation.

Intrauterine Device (IUD)-Associated Changes (Fig. 1.17)

Fig. 1.17.

Reactive cellular changes associated with intrauterine contraceptive device. Glandular cells with cytoplasmic vacuoles displacing the nuclei. LBC liquid-based cytology preparation.

Atrophy (Figs. 1.18 and 1.19)

Fig. 1.18.

Negative for intraepithelial lesion or malignancy. Atrophy. Maturation is not observed. Smear consists predominantly of parabasal cells. LBC liquid-based cytology preparation.

Fig. 1.19.

Negative for intraepithelial lesion or malignancy. Atrophy. Granular background, basal cells, and “blue blobs”. CP conventional preparation.

Hyperkeratosis (HK )

Parakeratosis (PK) (Fig. 1.20)

Fig. 1.20.

Reactive cellular changes. Parakeratosis. Superficial squamous cells with uniform, pyknotic nuclei. LBC liquid-based cytology preparation.

Chronic Follicular (Lymphocytic) Cervicitis (Fig. 1.21)

Fig. 1.21.

Reactive cellular changes. Chronic lymphocytic cervicitis. Polymorphous population of lymphoid cells with tingible body macrophages. LBC liquid-based cytology preparation.

Folic Acid Deficiency

Navicular Cells

Decidual Cells (Figs. 1.22, 1.23, and 1.24)

Fig. 1.22.

Decidua. These cells were observed on a Pap smear from a pregnant woman. They show abundant eosinophilic to amphophilic cytoplasm and enlarged nuclei with smudged chromatin pattern. CP conventional preparation.

Fig. 1.23.

Decidua. These cells show a high nuclear to cytoplasmic ratio and cytomorphologically mimic ASC-H. LBC liquid-based cytology preparation.

Fig. 1.24.

Decidua. From same patient as Fig 1.23 demonstrating round cells with abundant cytoplasm. There are occasional cells with high nuclear to cytoplasmic ratio (histology, H&E).

Trophoblasts

Atypical Squamous Cells (ASC)

Atypical Squamous Cells of Undetermined Significance (ASC-US) (Figs. 1.25, 1.26, and 1.27)

Fig. 1.25.

ASC-US . Atypical intermediate squamous cells with round hyperchromatic nuclei that are at 2.5–3 times the size of the adjacent normal intermediate cell nuclei. LBC liquid-based cytology preparation.

Fig. 1.26.

ASC-US. Intermediate cells with nuclear enlargement. No inflammation is present in the background. LBC liquid-based cytology preparation.

Fig. 1.27.

ASC-US . Atypical parakeratosis. Spindled and slightly pleomorphic orangophilic parakeratotic cells with mild nuclear enlargement. LBC liquid-based cytology preparation.

♦

Represents greater than 90% of all ASC. The average reporting rate is 4.5–5.0% of Pap tests

 

♦

The ASC-US-LSIL Triage Study (ALTS) trial showed that approximately 50% of patients with ASC-US have oncogenic high-risk HPV (HR-HPV) types

 

Cytologic Features

♦

ASC-US may manifest a wide range of cytologic features. Designation by cell type of origin is not used; however, these are listed below to assure recognition of ASC-US and to separate it from other, often overlapping, manifestations of reactive cells or more advanced cytologic epithelial abnormalities:

• 
  
  ASC-US involving intermediate or superficial squamous cells represents the most common pattern (Figs. 1.25 and 1.26). The cells are usually isolated and few in number. Nuclear size is 2½–3× size of an intermediate cell nucleus (70–120 μm²). There is a slight increase in N:C ratio. Minimal nuclear hyperchromasia, irregularity, clumping, smudging, or multinucleation may be observed. ASC-US cells do not include inflammatory or reparative/reactive “atypia”
  
  
• 
  
  ASC-US cells originating from squamous metaplastic cells have an enlarged nuclei 2× size of the nucleus of a normal immature squamous metaplastic cell. The cytoplasm distinguishes the nuclei as metaplastic; it is less abundant and more cyanophilic and dense. Additionally, the cells are more round with an N:C ratio higher than intermediate or superficial squamous cells
  
  
• 
  
  ASC-US may be used when atypical repair is present. Atypical repair has all the features of typical repair in addition to concerning cytologic features, such as cellular overlap, slight lack of cohesion, loss of nuclear polarity, anisonucleosis, and irregularity of nuclear contour. Prominent single or multiple nucleoli are present, as well as mitotic figures and an inflammatory background. If the “atypia” described above is prominent and concerning for HSIL or a more advanced lesion, then atypical repair can be considered under the ASC-H category
  
  
• 
  
  ASC-US may be seen in a background of atrophy. Normal atrophic specimens show nuclear enlargement with concomitant hyperchromasia, but if there is marked irregularities in cell shape, nuclear contours, or chromatin distribution, ASC-US may be reported
  
  
• 
  
  ASC-US can be used in the setting of atypical parakeratosis (Fig. 1.27). These cells demonstrate the cytologic features seen in parakeratosis except the nuclei are enlarged and more pleomorphic with irregular nuclear borders
  
  
• 
  
  Cells with equivocal changes for HPV are placed in the ASC-US category. These cells manifest partial koilocytes or perinuclear halos without nuclear abnormalities. Bi- or multinucleation may be observed

 

Differential Diagnosis

♦

CP smears may manifest drying artifact that may cause the nuclei to appear larger and washed-out, thus simulating ASC-US. This phenomenon has been almost eliminated by LBC

 

♦

LSIL shows more marked nuclear enlargement (greater than 3× the size of an intermediate squamous cell nucleus), hyperchromasia, and irregularities of nuclear contour. HPV cytopathic effect is synonymous with SIL

 

Atypical Squamous Cells, Cannot Exclude HSIL (ASC-H) (Figs. 1.28 and 1.29)

Fig. 1.28.

ASC-H. Atypical immature metaplastic cells with enlarged nuclei and nuclear irregularity. Only rare atypical cells were present. The findings are not diagnostic of HSIL. LBC liquid-based cytology preparation.

Fig. 1.29.

ASC-H . Atypical immature metaplastic cells. LBC liquid-based cytology preparation.

♦

Defined as having cytologic changes that are suggestive of high-grade squamous intraepithelial lesion (HSIL), but lack ample cytomorphologic features for definitive interpretation

 

♦

Constitutes approximately 5% of all ASC. The median reporting rate is 0.2–0.3% of Pap tests

 

♦

The association of ASC-H with underlying CIN2 and CIN3 (30–40%) is lower than for HSIL, but sufficiently higher than for ASC-US. This warrants different clinical management recommendations for ASC-H compared to ASC-US. A few cases of ASC-H may have invasive carcinoma on biopsy (2–3%)

 

♦

The ALTS trial noted that approximately 70–80% of ASC-H cases have oncogenic HR-HPV types

 

Cytologic Features

♦

ASC-H may be observed as “atypical immature metaplastic cells.” These occur as small single cells or in tight clusters of usually less than 10 cells. These cells resemble normal metaplastic cells with amphophilic cytoplasm and high N:C ratio but have a slightly larger nuclear size (1.5–2.5× that of normal metaplastic cell nuclei) with nuclear irregularities and mildly hyperchromasia

 

♦

ASC-H can be used for loose clusters of cells demonstrating markedly atypical repair if the N:C ratio is high and there is nuclear pleomorphism present, raising the possibility of SIL or carcinoma in the differential diagnosis

 

♦

An interpretation of ASC-H may be rendered for thick tissue fragments or hyperchromatic crowded groups (see section below). The cells show loss of polarity or are difficult to completely visualize, but raise the possibility of HSIL

 

♦

ASC-H can also be used for rare isolated atypical small cells that do not show features of immature metaplastic cells. These cells demonstrate high N:C ratio, nuclear irregularities or grooves, and hyperchromasia, but without typical cytoplasmic changes seen in metaplastic cells

 

Differential Diagnosis

♦

ASC-US cells are usually mature squamous cells with low N:C ratio

 

♦

Immature metaplastic cells have regular round nuclei and uniform finely granular chromatin

 

♦

HSIL cells are usually more numerous, often occurring in syncytial aggregates, and demonstrate more pronounced nuclear hyperchromasia, nuclear irregularities, and coarse granular chromatin

 

♦

Endometrial cells are smaller, exfoliate in three-dimensional clusters, and have an eccentric nucleus with finely granular chromatin

 

♦

Histiocytes have foamy cytoplasm, bean-shaped nuclei, and low N:C ratio

 

Squamous Intraepithelial Lesions (SIL )

Low-Grade Squamous Intraepithelial Lesion (LSIL) (Figs. 1.30, 1.31, and 1.32)

Fig. 1.30.

LSIL Intermediate squamous cells with mild nuclear enlargement and nuclear contour irregularities. Perinuclear halos consistent with HPV effect are present. HPV human papillomavirus, LBC liquid-based cytology preparation.

Fig. 1.31.

LSIL . Intermediate squamous cells with enlarged nuclei and hyperchromasia. LBC liquid-based cytology preparation.

Fig. 1.32.

LSIL (CIN1). Disordered proliferation of dysplastic cells in the lower third of the epithelium and HPV effect toward the surface (histology, H&E).

Cytologic Features

♦

LSIL is characterized by nuclear enlargement greater than 3× size of an intermediate squamous cell nucleus (often 5–6× the size, greater than 150 μm²), hyperchromasia, and nuclear irregularities. The chromatin pattern is usually finely granular and uniformly distributed. Nucleoli are generally inconspicuous or absent

 

♦

HPV cytopathic effect is characterized by large perinuclear halos with sharp borders and dense surrounding peripheral cytoplasm (koilocytes). The nuclei of koilocytes are enlarged and hyperchromatic with slightly irregular nuclear contours

 

♦

Dyskeratosis, binucleation, multinucleation, and nuclear pleomorphism may be observed in these cells. Tumor diathesis is absent

 

♦

LSIL in LBC may demonstrate decreased hyperchromasia, increased nuclear detail, and more apparent nuclear membrane irregularities compared to CP smears

 

Differential Diagnosis

♦

HSIL exhibits significant increase in the N:C ratio, hyperchromasia, and marked chromatin irregularities. The cells are usually arranged in syncytial aggregates

 

♦

ASC-US cells tend to be few in number and have slight nuclear enlargement (2.5–3× intermediate cell nucleus). The chromatin pattern in ASC-US is finer and the nuclear membranes are less irregular

 

♦

LSIL cannot exclude HSIL (LSIL-H): Occasionally, a specimen is encountered with cytologic features that lie between LSIL and HSIL, especially if there are few cells that meet criteria of ASC-H that are identified in a background of LSIL. The 2014 Bethesda system nomenclature maintains that classification into either LSIL or HSIL is possible in most instances. The Bethesda system does not advocate the use of LSIL-H category, which does not have an associated ASCCP management guideline. There will remain, however, an occasional case in which it is not possible to categorize an SIL and a comment explaining the nature of the uncertainty may be employed. An interpretation of ASC-H may be made in addition to a LSIL interpretation, which should lead to colposcopic evaluation, especially in young women. This dual interpretation should comprise only a minority of cases

 

High-Grade Squamous Intraepithelial Lesion (HSIL) (Figs. 1.33, 1.34, 1.35, 1.36, and 1.37)

Fig. 1.33.

HSIL . Metaplastic cells with enlarged nuclei, irregular nuclear contours, and coarse chromatin pattern. Subsequent biopsy revealed HSIL (CIN2). LBC liquid-based cytology preparation.

Fig. 1.34.

HSIL . Loose arrangement of small immature cells with high nuclear to cytoplasmic ratio, markedly irregular nuclear contours, and coarsely granular chromatic pattern (subsequent biopsy revealed HSIL/CIN2). CP conventional preparation.

Fig. 1.35.

HSIL . Syncytial cluster of small cells with very high nuclear to cytoplasmic ratio, markedly irregular nuclear contours, and coarse but equally distributed chromatic pattern. LBC liquid-based cytology preparation.

Fig. 1.36.

HSIL . Syncytial cluster of cells with enlarged nuclei, irregularities of nuclear contour, and coarse chromatin pattern. (Subsequent biopsy revealed HSIL/CIN3). LBC liquid-based cytology preparation.

Fig. 1.37.

CIN3. Severe dysplasia (carcinoma in situ). Full-thickness disordered maturation with dysplastic cells showing hyperchromatic nuclei and high nuclear to cytoplasmic ratio (histology, H&E).

♦

The focus of cervical cancer screening is primarily aimed at detection and treatment of HSIL

 

Cytologic Features

♦

HSIL shows increased N:C ratio (the overall cell size and nuclear size, however, are smaller than LSIL) and abnormal nuclear features. In LBC, the nuclear membrane irregularities are distinctly prominent, and hyperchromasia is often observed as coarsening of chromatin material rather than darkening of the nuclear stain in CP smears. Generally, HSIL cells tend to be round to oval with lacy, delicate, or metaplastic cytoplasm

 

♦

HSIL often occurs in cell aggregates (hyperchromatic crowded groups) and syncytial-like arrangements. In LBC, HSIL cells may be fewer in number and more isolated or present in small groups due to processing. Tumor diathesis is absent

 

♦

“ Keratinizing dysplasia” refers to the pleomorphic appearance of the cells rather than cytoplasmic staining. The cells exhibit pleomorphism with marked anisonucleosis (caudate, spindle, elongated, tadpole, or bizarre forms) and dense orangophilic cytoplasm with distinct borders. It can be difficult to grade keratinizing dysplasia because it may show a greater degree of pleomorphism

 

Differential Diagnosis

♦

Other causes of hyperchromatic crowded groups can be confused with HSIL

 

♦

Invasive SCC is characterized by marked cellular pleomorphism, prominent nucleoli, and the presence of tumor diathesis

 

♦

Endocervical adenocarcinoma in situ (AIS) is characterized by a picket-fence arrangement of columnar cells with peripheral palisading (“feathering”) and granular cytoplasm. The nuclei are usually oval and monotonous. This contrasts with the disordered syncytial arrangement of HSIL cells, which are smaller and exhibit variation in nuclear size and shape. HSIL is much more common than AIS and in difficult cases an interpretation of HSIL is generally rendered. A note can be added that the possibility of glandular origin cannot be excluded

 

♦

It may be also difficult to distinguish keratinizing dysplasia from keratinizing squamous cell carcinoma (KSCC) . KSCC generally has less cohesive cells and more marked nuclear pleomorphism. As such, keratinizing dysplasia is sometimes designated as SIL-ungraded to assure that a biopsy is obtained to evaluate for the presence of invasive carcinoma

 

Cervical Squamous Cell Carcinoma (SCC ) (Figs. 1.38, 1.39, 1.40, and 1.41)

Fig. 1.38.

Squamous cell carcinoma (keratinizing type). Markedly pleomorphic orangophilic cells are present. The nuclei are irregular with enlarged hyperchromatic nuclei and irregular coarse chromatin pattern. LBC liquid-based cytology preparation.

Fig. 1.39.

Invasive squamous cell carcinoma , keratinizing type. Keratin pearls are present in this invasive moderately differentiated squamous cell carcinoma (histology, H&E).

Fig. 1.40.

Squamous cell carcinoma (large cell nonkeratinizing type). Cluster of malignant cells with pleomorphic nuclei, irregular chromatin pattern, and nucleoli. LBC liquid-based cytology preparation.

Fig. 1.41.

Squamous cell carcinoma, large cell nonkeratinizing type. Invasive squamous cell carcinoma that lacks squamous pearls (histology, H&E).

Hyperchromatic Crowded Groups (HCG )

Tubal Metaplasia (Figs. 1.42 and 1.43)

Fig. 1.42.

Negative for intraepithelial lesion or malignancy. Endocervical cells, tubal metaplasia. A strip of ciliated columnar endocervical cells. LBC liquid-based cytology preparation.

Fig. 1.43.

Tubal metaplasia . Ciliated tubal epithelium lines an endocervical gland (histology, H&E).

Microglandular Endocervical Hyperplasia

Arias-Stella Reaction

Benign Glandular Cells in the Specimens from Post-Hysterectomy Women

Atypical Endocervical Cells (AEC ) (Fig. 1.44)

Fig. 1.44.

Atypical endocervical cells . A strip of pseudostratified atypical endocervical cells. LBC liquid-based cytology preparation.

Atypical Endocervical Cells, Favor Neoplastic (Fig. 1.45)

Fig. 1.45.

Atypical endocervical cells, favor neoplastic. A strip of pseudostratified atypical endocervical cells and a disorganized cluster of similar cells. The findings fall short of those characteristic of AIS. LBC liquid-based cytology preparation.

Endocervical Adenocarcinoma In Situ (AIS ) (Figs. 1.46, 1.47, and 1.48)

Fig. 1.46.

AIS. Hyperchromatic endocervical cells with pseudostratification and feathering. LBC liquid-based cytology preparation.

Fig. 1.47.

AIS. High power image of three-dimensional clusters of endocervical cells with enlarged elongated nuclei and coarsely granular chromatin. LBC liquid-based cytology preparation.

Fig. 1.48.

AIS. Endocervical gland with pseudostratification of enlarged hyperchromatic elongated nuclei adjacent to normal endocervical glandular epithelium (histology, H&E).

♦

Preservation of normal glandular architecture with involvement of part or all of the epithelium lining glands or the surface

 

♦

Associated with HPV 16 and 18 in 90% of cases

 

♦

Approximately 30–50% of AIS cases are associated with SIL

 

Cytologic Features

♦

“Endocervical type” of AIS is characterized by moderate to high cellularity of tight clusters and cohesive sheets of glandular cells showing pseudostratification, rosette formation, palisades, secondary gland openings, and feathering at the edge of sheets. The abnormal endocervical cells have uniform nuclear enlargement, hyperchromasia, nuclear irregularities, and crowding with elongated nuclei

 

♦

In LBC, AIS may manifest as hyperchromatic crowded groups (see above). These cells have dense immature cytoplasm, increased N:C ratio, large nuclei (70 μm²), nuclear overlap, even chromatin with coarse granularity, micronucleoli, mitosis, and apoptotic bodies. There is often difficulty with visualization of individual nuclei in the groups; a “disordered honeycomb” arrangement suggests an endocervical origin. Some architectural features may be more subtle in LBC, for example, the margins of the groups become smoother and sharper with lesser degrees of nuclear protrusion (feathering), but pseudostratified should still be evident

 

♦

The cytoplasm is delicate and finely vacuolated or granular with diminished mucin production

 

♦

The background is usually clean or inflammatory

 

Differential Diagnosis

♦

Tubal metaplasia is characterized by the presence of scant cellularity and cells with terminal bars and cilia. The nuclei are round to oval and more evenly spaced than those observed in AIS and the chromatin is finely granular. Mitoses, apoptosis, and nuclear hyperchromasia are not observed

 

♦

Repair/reactive cells are characterized by the presence of flat sheets of polygonal cells in a distinct honeycomb arrangement. Single atypical cells are absent. The cells have abundant cytoplasm and well-delineated cell borders. They are uniform cells with low N:C ratio. Minor degrees of nuclear overlap, nuclear enlargement, and variation in nuclear size and shape may be seen. The chromatin remains fine in reactive/reparative processes, but nucleoli can be prominent

 

♦

Microglandular hyperplasia is not distinctly recognized on cytology. Most cells look like normal endocervical cells or may assume repair-like features

 

♦

Cells derived from lower uterine segment endometrium typically occur as cohesive aggregates (tissue fragments) of a biphasic mixture of glandular and stromal cells (Fig. 1.49). The cell aggregates are large with tubular branched glands that may fold and appear three-dimensional. Feathering and palisading are absent. Cell polarity is retained. The nuclei are smaller and more uniform than those of AIS and have finely granular chromatin

Fig. 1.49.

Lower uterine segment endometrium can mimic AIS. Branching fragment of epithelial and stromal cells. LBC liquid-based cytology preparation.

 

♦

HSIL involving endocervical glands may show feathering; however, it is often restricted to one end of a crowded sheet. HSIL cells are usually arranged in large syncytial aggregates with ill-defined cell borders and loss of polarity. HSIL cells have dense cytoplasm and hyperchromatic nuclei with nuclear membrane irregularities. Strips, rosettes, or pseudostratified atypical columnar cells that are characteristic of AIS are not observed in HSIL. Unlike AIS, numerous normal endocervical cells and individual dysplastic squamous cells are typically present in the background in HSIL. Since AIS is much less frequent than HSIL (0.01% compared to 0.2–0.4%), the latter interpretation should statistically be more likely to represent the true cervical abnormality (Figs. 1.50 and 1.51)

Fig. 1.50.

HSIL involving endocervical glands mimicking AIS. Syncytial cluster of HSIL in a tight cluster with rounded contour. LBC liquid-based cytology preparation.

Fig. 1.51.

CIN3; severe dysplasia/carcinoma in situ involving endocervical glands. The endocervical glands are occupied by dysplastic squamous cells extending from the surface (histology, H&E).

 

Endocervical Adenocarcinoma (Figs. 1.52 and 1.53)

Fig. 1.52.

Adenocarcinoma , endocervical. Columnar cells with eccentric large round to oval nuclei, irregular chromatin, and nucleoli. CP conventional preparation.

Fig. 1.53.

Adenocarcinoma, endocervical. Adenocarcinoma cells with suggestion of a columnar configuration and glandular foundation. The nuclei are elongated and hyperchromatic with irregularly distributed chromatin pattern and nucleoli. The cytoplasm is basophilic and granular. Tumor diathesis is present in the background. CP conventional preparation.

Cytologically Normal Endometrial Cells (Figs. 1.54 and 1.55)

Fig. 1.54.

Endometrial cells, present in 45 years and older. Tight cluster of small glandular cells with eccentric nuclei and scant cytoplasm. The nuclei are uniformly round with regularly distributed chromatin. LBC liquid-based cytology preparation.

Fig. 1.55.

Endometrial cells, cytologically normal exodus. A tight ball of cells with central stromal cells and peripheral glandular cells. LBC liquid-based cytology preparation.

Atypical Endometrial Cells (AEM ) (Fig. 1.56)

Fig. 1.56.

Atypical endometrial cells. Tight cluster of endometrial cells with loss of polarity, variation in nuclear size and shape, coarse chromatin pattern, and scattered small nucleoli. LBC liquid-based cytology preparation.

Endometrial Adenocarcinoma (Figs. 1.57 and 1.58)

Fig. 1.57.

Adenocarcinoma, endometrial. Three-dimensional cluster of malignant glandular cells with round eccentric nuclei, vacuolated basophilic cytoplasm, and macronucleoli. LBC liquid-based cytology preparation.

Fig. 1.58.

Adenocarcinoma, endometrial. A cluster of pleomorphic malignant glandular cells with eccentric irregular nuclei, irregular chromatin, and macronucleoli. LBC liquid-based cytology preparation.

Small Cell Carcinoma of Cervix (Figs. 1.59 and 1.60)

Fig. 1.59.

Small cell carcinoma . Malignant small cells with high nuclear: cytoplasmic ratio, molding, and single-file arrangement. LBC liquid-based cytology preparation.

Fig. 1.60.

Small cell carcinoma. Small blue cells with molding and necrosis (histology, H&E).

Papillary Serous Adenocarcinoma (Fig. 1.61)

Fig. 1.61.

Vaginal specimen. Adenocarcinoma, metastatic to vagina from primary ovarian papillary serous carcinoma. Three-dimensional cluster of malignant glandular cells with prominent nucleoli. LBC liquid-based cytology preparation.

Extrauterine Metastatic Adenocarcinoma

Malignant Mixed Müllerian Tumor (MMMT )

Lymphoma/Leukemia Cervix

Screening Guidelines

The American Society for Colposcopy and Cervical Pathology (ASCCP) Guidelines (2012)

Primary HPV Testing

Quality Assurance (QA) Indicators

Adequacy Criteria

Anal Squamous Intraepithelial Neoplasia (SIL )/Anal Intraepithelial Neoplasia (AIN ) (Fig. 1.62)

Fig. 1.62.

HSIL in an anal Pap test. High nuclear to cytoplasmic ratio, hyperchromasia, course nuclear chromatin, and irregular nuclear borders. LBC liquid-based cytology preparation.

Anal Squamous Cell Carcinoma (SCC )

Paget Disease

Melanoma

Organisms

Overview

Key Cellular Features

Benign Cellular Features

♦

Centrally located, single or multiple, round to oval nuclei

 

♦

Chromatin finely granular and evenly distributed

 

♦

Nuclear membrane smooth

 

♦

Single or multiple, small, rounded nucleoli

 

♦

Normal N:C ratio

 

♦

Well-defined cytoplasmic border

 

♦

Tissue fragments are one- to two-cell layers with good polarity or honeycomb pattern

 

Reactive Cellular Features Due to Inflammation

♦

Centrally located, single or multiple, round to oval nuclei

 

♦

Nuclei enlarged with slightly enlarged nucleoli

 

♦

N:C ratio normal or slightly increased

 

♦

Chromatin slightly more granular and may be hyperchromatic

 

♦

Nuclear membrane may be wavy but uniform in thickness

 

♦

Background with inflammation and granular and cellular debris

 

Degenerative Changes Due to Reversible Injury

♦

Nuclear enlargement due to swelling (karyolysis)

 

♦

Chromatin smudged or washed-out

 

♦

Nuclear membrane may be uneven in thickness

 

♦

Nucleoli may be indistinct

 

♦

Cells may become more rounded due to swelling

 

♦

Cytoplasmic disintegration and fraying (moth-eaten appearance)

 

♦

Cell borders not well defined

 

♦

Normal N:C ratio

 

♦

Background may or may not be inflamed

 

Degenerative Features Due to Irreversible Injury

♦

Nucleus wrinkled and decreased in size

 

♦

Loss of chromatin detail

 

♦

Pyknotic and smudged chromatin

 

♦

Fragmentation and condensation of chromatin (karyorrhexis)

 

♦

Hyperchromasia

 

♦

Nucleolus invisible

 

♦

Cytoplasmic borders not well defined and disintegrated

 

♦

N:C ratio may be increased due to loss of cytoplasm or decreased due to nuclear shrinkage

 

Cellular Features of Repair (Fig. 1.63)

Fig. 1.63.

Repair, gastric brush. Monolayer sheet of well-organized cells with striking resemblance to each other. No cellular overlap. The nuclei are enlarged with prominent nucleoli and marginated, pale chromatin. The cell borders are well defined, and the cytoplasm shows streaming in the same direction. Papanicolaou stain, high power view.

♦

Monolayer sheets of well-organized cells and very few single cells

 

♦

Cells bear striking resemblance to each other

 

♦

Little or no cellular overlap

 

♦

Enlarged cells with centrally located round nuclei

 

♦

Enlarged nuclei

 

♦

Prominent nucleoli/cherry red single macronucleoli

 

♦

Marginated chromatin (swelling)

 

♦

Well-defined, uniform, and thick nuclear membrane

 

♦

Well-defined cell borders

 

♦

Cytoplasm may be streaming in the same direction (school of fish)

 

Atypical Repair

♦

Areas of atypical repair usually merge or coexist with typical repair

 

♦

Anisonucleosis within the monolayer sheet

 

♦

Increased cellular overlap within the sheet

 

♦

Increased number of single cells

 

♦

Increase chromatin granularity

 

♦

Altered nuclear polarity

 

♦

Hyperchromasia

 

♦

Cell borders blurred

 

General Features of Malignancy

♦

Increased N:C ratio (with few exceptions)

 

♦

Nuclei are round to oval, single or multiple, and frequently irregular

 

♦

Marked variation in nuclear size and shape (anisonucleosis)

 

♦

Chromatin is crisp and may vary from finely granular and evenly distributed to coarsely granular and unevenly distributed

 

♦

Chromatin rim may be irregular in thickness

 

♦

Nuclear membrane may be smooth but frequently irregular with grooves and sharp notches

 

♦

Nucleoli may vary from inconspicuous to prominent. They may be angulated or irregular

 

♦

Cellular discohesion with many single cells

 

♦

Cells within aggregates lose their polarity and form pseudosyncytia (cells blend with each other and lose their well-defined borders)

 

♦

Background may contain tumor diathesis which appears as granular material with cellular debris and old blood

 

Respiratory Cytology

Benign Lesions

Pneumonia

Microscopic

♦

Specimens from bacterial pneumonia are cellular and consist predominantly of numerous polymorphonuclear leukocytes that may obscure other elements such as native respiratory cells. The background may contain cellular debris that mimics tumor diathesis and careful screening of smears with purulent material is warranted to rule out a necrotic tumor

 

♦

The presence of bacterial colonies is significant only in FNA samples and additional passes should be requested for cultures

 

♦

Specimens from fungal pneumonia particularly blastomycosis can contain severe acute inflammation, and smears need to be carefully screened to detect the spores

 

♦

Specimens from viral pneumonia will have high lymphocytic background

 

♦

Smears representing either viral or fungal pneumonia may contain scattered highly atypical squamous cells

 

♦

Other cellular changes such as reactive, e.g., creola, bodies or repair and degenerative features may be present

 

Differential Diagnosis

♦

Unsatisfactory exfoliative specimen due to oropharyngeal contamination. These samples tend to contain other contaminants such as squamous cells, Actinomyces, and Candida

 

♦

KSCC, when atypical squamous cells are present. Carcinoma usually presents with higher numbers of malignant cells with well-preserved hyperchromatic nuclei while those in pneumonia tend to show evidence of degenerative changes. The presence of viral inclusions or fungal elements is a clue to the nature of the atypia

 

Creola Bodies (Bronchial Cell Hyperplasia) (Fig. 1.64)

Fig. 1.64.

Creola body, bronchoalveolar lavage. Three-dimensional, tightly cohesive clusters bordered by cilia. Papanicolaou stain, high power view.

Clinical

♦

Originally described in asthmatic patients. The term “creola” was coined in honor of the patient whose sputum contained such clusters. Now it is established that such clusters can be seen in a variety of reactive conditions

 

Microscopic

♦

The smears can be very cellular and contain numerous tight clusters of benign reactive columnar ciliated cells Florid cases may contain papillary tissue fragments or three-dimensional cell balls

 

♦

These clusters are characterized by the presence of peripheral palisading cells with terminal plates and cilia sometimes intermixed with an occasional goblet cell. Central cells are smaller, less differentiated, and difficult to visualize clearly

 

Differential Diagnosis

♦

Adenocarcinoma

• 
  
  Clusters of highly atypical cells with nuclei situated at the periphery. There is usually evidence of cell discohesion, mitotic activity, and apoptotic figures. Bronchial hyperplasia, despite the cellularity, does not exhibit any of these malignant features. The presence of goblet cells and terminal cilia is clue to the benign nature of the cells

 

Pneumocyte Type II Hyperplasia

Clinical

♦

These cells are the result of regeneration after injury replacing the type I pneumocyte. Injury could have resulted from a variety of conditions including pneumonia, pulmonary infarction, diffuse alveolar damage (DAD), etc

 

Microscopic

♦

The number of cells may vary from few to numerous. The atypical pneumocytes may present as single cells, small clusters, or many large clusters. The latter is mainly encountered in cases with DAD

 

♦

The clusters are tightly cohesive with scalloping borders due to protruding nuclei at the periphery. The cells may have slightly enlarged nuclei but relatively normal or slightly increased N:C ratio

 

♦

The cells can be highly vacuolated and the vacuoles are frequently out of proportion with the cellular size

 

♦

Background may contain evidence of other reactive changes such as repair

 

Differential Diagnosis

♦

Bronchial cell hyperplasia

• 
  
  Clusters have focal areas with well-visualized terminal bars and cilia. Clusters may be in continuation with rows of reactive bronchial cells

 

♦

Adenocarcinoma

• 
  
  Present with more obvious atypia and evidence of discohesion. They tend to be finely vacuolated, rather than the large out of proportion vacuoles seen in pneumocyte hyperplasia

 

Pulmonary Infarct

Clinical

• 
  
  These are usually aspirates performed when a localized lesion is seen in a patient with a clinically undetected embolic event

Microscopic

♦

Smears are variable in cellularity and content depending on the area sampled. Sheets and papillary groups of reactive pneumocytes may be seen if the periphery of the lesion is sampled, while atypical squamous metaplastic cells are seen when the center is sampled

 

♦

Hemosiderin-laden macrophages may be present in the background and are a clue to the diagnosis

 

♦

Maximum atypia is seen during second to third postinfarction weeks

 

Differential Diagnosis

♦

Adenocarcinoma:

• 
  
  The cells are more pleomorphic and discohesive with obvious disorganized arrangement within the sheets or clusters

 

Cigarette and Habitual Marijuana Smoking

♦

The smears of exfoliative samples are generally cellular with features of irritation and consequent reactive changes

 

♦

The earliest change is reserve cell hyperplasia, which presents as tight clusters of uniform small cells with hyperchromatic nuclei This is followed by squamous metaplasia (Fig. 1.65)

Fig. 1.65.

Reserve cell hyperplasia, bronchial wash. Tightly cohesive small blue cells with no cytologic atypia or discohesion. The presence of contiguous goblet cells is a clue of their origin. Papanicolaou stain, high power view.

 

♦

Background of numerous multinucleated histiocytes frequently containing anthracotic pigment

 

Radiation and Chemotherapy-Induced Atypia (Fig. 1.66)

Fig. 1.66.

Radiation therapy change, lung, FNA. Cytomegalic cells arranged in a syncytium. The cells are bizarre with amphophilic, frequently vacuolated cytoplasm and ingested neutrophils. The chromatin is frequently smudged and difficult to read. Papanicolaou stain, high power view.

Clinical

♦

Patients undergoing treatment for a malignant disease

 

♦

Acute radiation therapy changes are seen within 6 months of initiating treatment, while chronic changes may persist for a long time. Chemotherapy changes resemble those of chronic radiation and subside within a month of terminating therapy

 

Microscopic

♦

Acute radiation therapy:

• 
  
  Cytomegaly, nucleomegaly, multinucleation, and normal N:C ratio
  
  
• 
  
  Cytoplasmic vacuolization and neutrophil ingestion (vacuoles may be prominent) and cytoplasmic polychromasia
  
  
• 
  
  Syncytial sheets with blurred cell borders. Cytoplasm may be very fragile and blend with the background

 

♦

Chronic radiation and chemotherapy changes

• 
  
  Cytomegaly, nucleomegaly, multinucleation, and normal N:C ratio
  
  
• 
  
  Syncytial sheets with blurred cell borders
  
  
• 
  
  Bizarre cells with amphophilic cytoplasm, indistinct cell border, and cytophagocytosis of neutrophils
  
  
• 
  
  Nuclear degeneration (karyorrhexis and karyolysis), hyperchromasia, and prominent nucleoli
  
  
• 
  
  Smudged chromatin and poor nuclear detail

 

Differential Diagnosis

♦

Poorly differentiated carcinoma:

• 
  
  These malignant cells will have increased N:C ratio. The nuclei are hyperchromatic and frequently contain prominent nucleoli. The chromatin is well preserved and nuclear detail is evident

 

Amiodarone-Induced Changes

Clinical

♦

Patients treated with amiodarone for supraventricular arrhythmia

 

♦

Patients present with nonspecific symptoms such as cough, shortness of breath, etc. and frequently have bilateral diffuse lung infiltrates

 

Microscopic

♦

Cellular smears consisting of numerous foamy alveolar macrophages with uniform, well-defined, and distended vacuoles. These cells are negative for oil red O stain

 

♦

Atypical pneumocytes with increased N:C ratio, hyperchromasia, and nuclear pleomorphism

 

♦

Background of increased lymphocytes, neutrophils, and eosinophils

 

Electron Microscopy

♦

Osmiophilic lamellar cytoplasmic inclusions

 

Differential Diagnosis

♦

Lipoid pneumonia (Fig. 1.67)

Fig. 1.67.

Lipoid pneumonia, bronchoalveolar lavage. Lipid-laden macrophages with highly vacuolated cytoplasm. Papanicolaou stain, high power view.

• 
  
  Patient presentation is different and lack history of amiodarone therapy (see below)
  
  
• 
  
  Vacuoles are less defined and positive for oil red O

 

Hemosiderin-Laden Macrophages

Clinical

♦

Pediatric patients

• 
  
  Idiopathic pulmonary hemosiderosis (isolated)
  
  
• 
  
  Pulmonary hemosiderosis associated with sensitivity to cow’s milk
  
  
• 
  
  Glomerulonephritis
  
  
• 
  
  Collagen vascular and pruritic disease
  
  
• 
  
  Cardiac diseases, intravascular lesions, or malformations

 

♦

Adult patients

• 
  
  Diffuse interstitial pulmonary disease
  
  
• 
  
  Congestive heart failure (heart failure cells)
  
  
• 
  
  Hypersensitivity pneumonitis
  
  
• 
  
  Fibrosis associated with rheumatoid arthritis
  
  
• 
  
  Radiation or chemotherapy

 

Microscopic

♦

Smears contain many pigmented histiocytes. Hemosiderin appears as refractile particles that vary in size and stains as golden brown with Papanicolaou and as greenish brown with Diff-Quik stain

 

Quantitation of Hemosiderin-Laden Macrophages

♦

Percentage of cells containing hemosiderin (Prussian blue or Perl stain)

• 
  
  Result of >20% has a sensitivity of 10% and specificity of 92% for detecting pulmonary hemorrhage and hemosiderosis

 

♦

Hemosiderin score

• 
  
  Adding staining intensity score (0–3) for each 100 cells measured
  
  
• 
  
  A score of >50 has a high sensitivity and specificity in the proper clinical setting

 

Differential Diagnosis

♦

Carbon-laden histiocytes (dust cells)

• 
  
  These cells are commonly seen in all samples and are particularly increased in smokers. They contain anthracotic pigment which is nonrefractile and shows minimal variation in size. The pigment stains dark brown or black on both Papanicolaou and Diff-Quik stains

 

♦

Melanophages

• 
  
  These cells are seen in patients with history of melanoma but are not always associated with the malignant cells. The pigment varies from fine dust like quality to globular droplets and stains brown to black

 

Lipid-Laden Macrophages in Bronchial Lavage (See Fig 1.67)

Clinical

♦

Associated with tracheal aspiration in children with gastroesophageal reflux (GER) or lobular consolidation distal to an obstructed bronchus. In adults it may also be associated with aspiration of mineral oil

 

Microscopic

♦

Smears with finely vacuolated histiocytes admixed with bronchial cells. Vacuoles are fine and ill defined

 

♦

Fresh specimens should be stained with oil red O to confirm the diagnosis

 

♦

Quantitation/percentage of oil red O-positive cells may be of value for predicting recurrent aspiration

 

Corpora Amylacea (Fig. 1.68)

Fig. 1.68.

Corpora amylacea , bronchial wash. Thick amorphous material with internal rings. Note the crack induced during preparation and the surrounding giant cell. Papanicolaou stain, high power view.

Clinical

• 
  
  Their presence has no particular clinical significance and is seen in patients with:
  

  
  

  ♦
  

  
  

  Older age

  
  

   

  
  

  ♦
  

  
  

  Heart failure

  
  

   

  
  

  ♦
  

  
  

  Pulmonary infarction

  
  

   

  
  

  ♦
  

  
  

  Chronic bronchitis

  
  

   

Microscopic

♦

Variably sized round to oval dense bodies that stain amphophilic with Papanicolaou stain. They have concentric laminations and a radiating array arising from a central nidus. They frequently crack during smearing and can be seen phagocytosed by giant cells

 

♦

They are positive for periodic acid-Schiff (PAS) stain and resist digestion and are weakly positive with Congo red stain

 

Differential Diagnosis

♦

Alveolar proteinosis

• 
  
  Patients are symptomatic with dyspnea, dry cough, and fever. Radiologically, these patients have extensive bilateral consolidation. The material stains strongly positive with PAS and resists digestion and is also positive to oil red O stain but negative to mucin stains

 

♦

Amyloid

• 
  
  Patients may have systemic amyloidosis or history of lymphoma or carcinoid. Amyloid is rarely detected in exfoliative samples. It appears as flocculent irregularly shaped material that stains eosinophilic or cyanophilic with Papanicolaou stain and blue with Diff-Quik stain. Amyloid stains with Congo red and exhibits apple green birefringence upon polarization. It can be weakly reactive to PAS

 

Alveolar Proteinosis

Clinical

♦

This autoimmune disease is characterized by accumulation of phospholipoproteinaceous material within the alveolar spaces. Patients present with nonspecific symptoms such as cough or dyspnea, but radiologically they may present with bilateral extensive consolidation that is way out of proportion with their symptoms. In up to 50%, the patients may present with patchy and perihilar infiltrate “bat wing pattern”

 

Microscopic

♦

The lavage is usually thick and grossly opaque

 

♦

Microscopically it appears as amorphous thick material with irregular shapes that stains basophilic with Diff-Quik and amphophilic with Papanicolaou stain. The material is also strongly positive to PAS and oil red O (on fresh smears) but negative to all mucin stains and Congo red

 

Differential Diagnosis

♦

Corpora amylacea (see above)

 

♦

Amyloid (see above)

 

Sarcoidosis(Fig. 1.69)

Fig. 1.69.

Sarcoidosis, FNA of lung. (A) Clusters of epithelioid histiocytes mixed with lymphocytes, Papanicolaou stain. (B) Diff-Quik stain, high power view.

Clinical

♦

This is a multiorgan disease that frequently affects the lung. Radiologically patients present with bilateral hilar and mediastinal lymphadenopathy and nodular lung infiltrate. The nodules are particularly numerous along the bronchi and vessels

 

Microscopic

♦

On FNA, may see loose clusters of epithelioid cells and giant cells intermingled with lymphocytes. These represent the noncaseating granulomata seen on histology

 

♦

BAL findings are not specific, but generally the number of lymphocytes and histiocytes is increased and many multinucleated giant cells can be detected. Schaumann bodies may be noted in the giant cells. Asteroid bodies are not specific. All microorganism stains are negative

 

Differential Diagnosis

♦

Other infectious diseases such as tuberculosis

• 
  
  Acid-fast bacilli may be detected by Ziehl–Neelsen stain in up to 40% of cases

 

♦

Other granulomatous diseases

• 
  
  Fungal infections: Granulomas are usually less cohesive and there may be evidence of necrosis and suppurative reaction especially with blastomycosis. Fungal spores and hyphae are detected and will stain with Gomori methenamine silver (GMS)

 

♦

Rheumatoid granulomas

• 
  
  Lung nodules are usually seen in severe cases and frequently associated with pleuritis and effusion. FNA will contain necrotic debris, scattered epithelioid histiocytes, and lymphocytes

 

Miscellaneous Findings

Ferruginous Bodies (Fig. 1.70)

Fig. 1.70.

Asbestos body, bronchial wash. Fiber with a clear, colorless center, and uniform thickness. Papanicolaou stain, high power view.

Clinical

♦

General term applied to a variety of mineral fibers that have been inhaled and sheathed with golden brown iron–protein complex. Asbestos bodies are indicative of occupational asbestos exposure

 

Microscopic

♦

Consist of a clear colorless central fiber of uniform thickness within a golden brown iron–protein complex

 

Differential Diagnosis

♦

Non-asbestos bodies: have a black or yellowish center that is not uniform in thickness

 

Ciliocytophthoria

Clinical

♦

The presence of this finding is usually suggestive of viral infection (e.g., respiratory syncytial virus)

 

Microscopic

♦

Scattered anucleated cytoplasmic fragments bearing cilia are seen among the normal component of an exfoliative specimen such as bronchial cells and histiocytes. These fragments represent detached bronchial cilia

 

Asthma

Clinical

♦

The following findings are frequently encountered in asthmatic patients although they are by no means specific to asthma:

• 
  
  Curschmann spirals
  

  
  

  •
  

  
  

  Appear as coiled strands of inspissated mucus frequently associated with bronchial cell hyperplasia

  
  

   
  
  
• 
  
  Charcot-Leyden crystals
  

  
  

  •
  

  
  

  Elongated red crystalline structures derived from eosinophil phospholipase B, involved in prostaglandin metabolism

  
  

   
  
  
• 
  
  Bronchial cell hyperplasia
  

  
  

  •
  

  
  

  Also known as “creola bodies” (see description above). This entity was first described as a characteristic of status asthmaticus, but it is believed now that it is rather a feature of chronic irritation and injury to the bronchial mucosa