The place of FNA in the investigative sequence

The utility and practice of tFNA of the prostate and the reasons for its success in our hospital have been reported previously.^8–10 Provided the pathologist is able to pinpoint nodules and indurations of the prostate by palpation with the index finger, and has dexterity in performing tFNA, the results of FNA match those obtained by TNCB.¹⁰

The three-tiered cytological classification for grading prostate cancer proposed by Esposti²⁷ has been shown to have prognostic value. An estimation of Gleason score can also be made on tFNA samples.¹⁰ As recently as 2007, Maksen et al.⁵ stated that gland size roughly determines Gleason pattern in liquid-fixed FNA samples. Prostatic intraepithelial neoplasia (PIN) should not be diagnosed by FNA alone. However, a highly cellular smear with pronounced atypia seems to rule out PIN.²⁸ Immunostaining has proven useful in FNA of the prostate.^5,29

tFNA is likely to continue to be used in view of economic considerations and recent health budget restraints because it is a simple and comparatively much cheaper technique than TCNB. We acknowledge that nowadays tFNA has been relegated in most Western countries, but it may still play a key role in developing countries.

Indications

Accuracy of diagnosis

Transrectal fine needle aspiration and US-guided TNCB using automated biopsy devices have a high and essentially equal accuracy in diagnosing prostate cancer.^4,5 A recent review of the literature¹⁰ produced a list of references commenting on the correlation between cytological grading and Gleason score and the accuracy of digitally guided tFNA compared with thick and US-guided TNCB. Prerequisites for acquisition of an acceptable level of competence in performing tFNA and interpreting the smears have been defined.³⁴

Tannenbaum et al.⁴ and Maksen et al.⁵ have described the features of benign prostatic cytology, the sources of atypical cells, the cytology of carcinoma, and the causes of false-negative and false-positive cytological diagnoses in liquid-fixed FNA collections, and Willems et al.³⁴ in conventional smears. The most common cause of a false-negative FNA is an inadequate sample. Dexterous pathologists rarely make a false-positive diagnosis. We have previously commented on the diagnostic challenges posed by atypical cells in smears of granulomatous prostatitis⁸ and on pitfalls and infrequent findings in FNA of the prostate.⁹ Basic rules to avoid pitfalls in FNA in different contexts have been put forward.³⁵ See also Chapter 5 in the seminal monograph by Zajicek³⁶ and Chapter 11 in the book by Linsk and Franzén.³⁷

Complications

The rare complications of tFNA were analyzed in a review of 14 000 patients with follow-up.³⁸ Transient hematuria is not uncommon. Fever may develop within 24 hours. Patients should be instructed to report promptly in both situations. In our experience of more than 10 000 tFNAs (using 23-gauge needles), no tumor seeding in the needle track has been observed after 5 to 10 years’ follow-up.

Contraindications

The only contraindication is symptomatic febrile prostatitis.³⁶ We have performed tFNAs in patients with inadvertent acute prostatitis without complications. tFNA can be performed in patients with hemorrhagic diathesis and in patients on anticoagulation therapy.

Technical considerations

Patients should be verbally informed of the whole procedure by the examining pathologist and a written informed consent requested. No special preparations for biopsy and no sedation are necessary. tFNA is carried out as an outpatient procedure. A urological lubricant helps to introduce the palpating finger. The most comfortable position for both patient and examining pathologist is the lithotomy position on a gynecological examination couch (Fig. 13.1A,B). A rapid feedback to urologists is essential to achieve success.

Fig. 13.1 t-FNA of the prostate

(A) The Franzén guide fitted to the left index finger covered with a finger cot; (B) Performing a tFNA of the prostate.

Appropriate training should ensure that the operator properly masters the technique of tFNA using the Franzén guide and a 20-cm long 23-gauge needle fitted to a disposable syringe and a Cameco holder (Cameco AB, Box 5519, Täby, S-183 05 Sweden, Pat no. 3819091). This is essential to minimise the proportion of unsatisfactory specimens and to increase the accuracy of the procedure. The examining pathologist must be proficient in digital examination of the prostate. Details about the biopsy technique can be found elsewhere.^34,37

We perform one or two tFNAs from each abnormal palpable zone; additional aspirates are taken from the opposite lobe even if apparently normal on palpation. This approach enables us to suggest at least a T2C stage if cancer cells are found in aspirates from both lobes. We use Diff-Quik (DQ)™ and Pap stain in parallel.

The gross aspect of the yield may predict the diagnosis even before microscopic examination: abundant, granular yield suggests carcinoma; a drop of blood-tinged fluid with particulate material suggests hyperplasia; hemorrhagic yield indicates that the needle is out of the prostate; a ‘non-representative’ smear obtained by a dexterous operator suggests stromal hyperplasia; abundant fluid suggests either urine or a cyst.

The importance of proficient training in smearing and distributing the yield onto several slides cannot be overemphasised (see Chapter 2). The three-step smearing technique is recommended for fluid yields in order to concentrate solid fragments into two bands. The yield is suitable for molecular studies.

Benign prostatic hyperplasia (BPH) (Fig. 13.2)^{4,5,34,36,37,39}

Fig. 13.2 Prostate, benign hyperplasia

Honeycomb-like sheets of uniform glandular epithelial cells; note visible cell borders and coarse cytoplasmic granules in A (A, DQ; B, Pap, HP).

Cohesive monolayered sheets of glandular epithelial cells can be quite large with distinct boundaries; most cells are seen on end and appear polygonal with centrally placed nuclei. The abundant pale cytoplasm and the distinct cell membranes give the sheet a honeycomb appearance (Fig. 13.2A,B). Only at the periphery are some cells seen in profile as columnar.

The main criteria of benignity are the uniform distribution of nuclei within monolayered sheets, distinct cell membranes, low N : C ratio and intracytoplasmic secretory granules (Fig. 13.2A). The granules stain dark magenta with DQ but are less conspicuous in alcohol-fixed Pap-stained smears. Although granules are not present in all benign epithelial cells, they are rarely present in carcinoma cells and absent in epithelial cells from rectal mucosa.

Other common findings in smears of BPH are: inflammatory cells, macrophages, metaplastic squamous epithelial cells, clumps of condensed secretion, fragments of calculi and corpora amylacea. Tiny fragments of stromal smooth muscle tissue are sometimes seen. Cytologic features of the central zone have been described in scrape smears of surgical specimens.⁴⁰

Prostatitis (Figs 13.3 and 13.4)^4,36,37,39

Fig. 13.3 Prostatitis (acute)

Irregular epithelial sheet with mildly enlarged nuclei; background of neutrophils (DQ, HP).

Fig. 13.4 Prostatitis (granulomatous)

Many epithelioid histiocytes, multinucleated giant cell with phagocytosed secretion; many neutrophils (DQ, IP).

Mild epithelial atypia is acceptable in the presence of significant inflammation (Fig. 13.3). The distribution of cells in epithelial sheets may be less regular than normal and the cell membranes less distinct. Nuclei may be mildly enlarged and varying in size. Cytoplasmic granules are often absent, while degenerative changes such as cytoplasmic vacuolation are often seen. However, prominent nuclear enlargement and pleomorphism, nucleolar enlargement and chromatin abnormalities do not occur. There is little tendency to dissociation of epithelial sheets, and microacini are not seen. As inflammation may coexist with carcinoma, epithelial atypia must be carefully evaluated. We require the presence of epithelial sheets encrusted with polymorphonuclears to arrive at the diagnosis of acute prostatitis.

Granulomatous prostatitis (Fig. 13.4)^36,37,39 remains a diagnostic dilemma since both clinical and cytological findings may mimic carcinoma. The cytological diagnosis of non-specific granulomatous prostatitis or tuberculous prostatitis, respectively, is based on the presence of epithelioid granulomas or obvious caseous necrosis. Nuclear overlapping, anisonucleosis, occasionally striking atypia, naked nuclei and some acinar formation may result in a false-positive diagnosis. Epithelial atypical cells in granulomatous prostatitis show a typical basophilia in DQ-stained smears; this basophilia is not seen in prostate carcinoma cells.

The diagnostic challenges posed by epithelioid aggregates and reactive changes in both duct/acinar and metaplastic cells have been discussed elsewhere.⁸

The cytological findings in malacoplakia of the prostate by FNA have been described.⁴¹

Adenocarcinoma of prostate (Figs 13.5–13.8)^{4,5,27,34,36,37,39}

Fig. 13.5 Well-differentiated adenocarcinoma

Cohesive sheets of atypical glandular epithelium; mild nuclear enlargement and anisokaryosis; crowding of nuclei; absence of cytoplasmic granules. Note microacinar pattern in B and prominent nucleoli and a mitotic figure in C (A and B, DQ; C, Pap, HP).

Fig. 13.6 Moderately-differentiated adenocarcinoma

Aggregate of malignant cells; marked nuclear enlargement and nuclear pleomorphism; nuclear crowding; microacinar pattern: indistinct cell borders. Note contrasting honeycomb sheet of benign epithelium (DQ, HP).

Fig. 13.7 Moderately-differentiated adenocarcinoma

Cellular smears of less cohesive malignant glandular epithelial cells; vesicular nuclei; prominent nucleoli. Note fragile vacuolated cytoplasm suggestive of a clear cell pattern in B (A, Pap; B, DQ, HP).

Fig. 13.8 Poorly-differentiated adenocarcinoma

Poorly cohesive malignant cells with large vesicular malignant nuclei and large nucleoli. Note small sheet of benign epithelium on right in A (A, DQ; B, Pap, HP).

In smears of prostatic carcinoma, sheets of benign glandular epithelial cells are commonly seen side-by-side with aggregates of malignant cells (Fig. 13.6), reflecting the diffusely infiltrative growth of the tumor. Benign and malignant cells can be directly compared (very helpful clue) and differences in cytoarchitectural features are easily appreciated. Nuclear enlargement is one of the most important criteria of malignancy. Nucleolar enlargement is better demonstrated in Pap-stained smears.

Absence of visible cell membranes, nuclear crowding and overlapping and dissociation of cells are other important criteria. The presence of coarse intracytoplasmic secretory granules makes malignancy unlikely, but they can occasionally be found in cells from well-differentiated adenocarcinoma. Cytoplasmic vacuolation may be seen in both benign and malignant cells. Nuclear pleomorphism and chromatin abnormalities are obvious in less well-differentiated cancers but may be subtle in well-differentiated carcinomas, rendering a definitive malignant diagnosis difficult (Fig. 13.5). Demonstration of basal epithelial cells by immunocytochemistry may be of help in the distinction between well-differentiated adenocarcinoma and adenosis or basal cell hyperplasia,⁵ but interpretation is more difficult than in histologic sections. Immunostaining is a useful tool for the diagnosis of prostate cancer at metastatic sites.⁴² Results may be conflicting in metastases of poorly differentiated carcinomas.

If only a small number of atypical cells are found in a predominantly benign cell population, great caution should be observed in making a definitive diagnosis of malignancy. Sources of atypical cells have been referred to elsewhere.^4,5,8,9 In case of doubt, the patient should be submitted to systematic TNCB taken according to a standardized protocol.

Regarding cytological grading of prostatic adenocarcinoma, see below and Figures 13.5 to 13.8.

Not infrequently, smears from BPH contain a few cohesive aggregates of cells with frank atypia that may represent PIN, basal cell or atypical hyperplasia, and can be mistaken for malignancy (Figs 13.9 and 13.10). However, they fall short of clear-cut criteria of malignancy; cell cohesion is maintained and microacini are rarely seen. The atypical cells usually constitute only a minor proportion of the cell population. The presence of nucleolar enlargement in some cells should not lead to the diagnosis of carcinoma since they may correspond to focal atypical hyperplasia.

Fig. 13.9 Basal cell (atypical) hyperplasia

Sheets of glandular epithelial cells showing mild nuclear enlargement and nuclear crowding contrasting with normal epithelium (A, DQ; B, Pap, HP).

Fig. 13.10 Basal cell hyperplasia

Corresponding tissue section (H&E, IP).

PIN should not be diagnosed by tFNA alone.²⁸ We use the term ‘atypical cells’ when the atypia and cellularity are below the requirements needed to reach a confident diagnosis of malignancy, and submit the patient for systematic TNCB. Histology of these cases almost always reveals either high-grade PIN or low-grade carcinoma. Pathologists should refrain from making a definitive diagnosis of malignancy when the smears contain only a small proportion of cells with malignant features.

Contamination of samples by epithelial cells from the rectal mucosa is common when tFNA is performed by an inexperienced operator.^36,37 Isolated tall cylindrical cells, palisaded rows, glandular structures and goblet cells intermingled with mucin and rectal content indicate rectal mucosal origin. Rectal cells lack intracytoplasmic granules (Fig. 13.11).

Fig. 13.11 Rectal contamination

Microglandular aggregates and palisading columnar epithelial cells; some mucin (DQ, IP).

Inadvertent aspiration of the seminal vesicle may yield large atypical cells that may mislead the unwary into an erroneous diagnosis of poorly differentiated carcinoma. Large hyperchromatic, often multilobated, pleomorphic, even bizarre, nuclei are seen.^9,36,37 Coarse intracytoplasmic granules of lipofuscin, which stain dark green–blue with DQ, brown with Pap or H&E, quite different from the secretory granules of prostate epithelium (Figs 13.12 and 13.13), dense aggregates of basophilic amorphous material and spermatozoa in the background indicate origin from seminal vesicle.

Fig. 13.12 Seminal vesicle epithelium

(A) Large bizarre nuclei; note occasional spermatozoa in the background (arrow) (DQ, HP); (B) Single epithelial cells with large pleomorphic nuclei; note coarse intracytoplasmic pigment (DQ, HP).

Fig. 13.13 Seminal vesicle epithelium

(A) Vaguely glandular aggregates of epithelial cells with pleomorphic and hyperchromatic nuclei; abundant cytoplasm with vacuoles and brown pigment granules (Pap, HP); (B) Corresponding tissue section (H&E, HP).

Ganglion cells may mimic malignant cells (Fig. 13.14).⁹

Fig. 13.14 Ganglion cells

Three large ganglion cells with prominent nucleoli next to a cluster of malignant cells. Notice a malignant acinus at the bottom-right corner. (DQ IP).

The differential diagnosis between prostatic adenocarcinoma and transitional cell carcinoma is discussed below. Pitfalls and infrequent findings in prostate aspirates, a list of benign conditions mimicking carcinoma and clues to diagnosis have been published elsewhere.⁹

Effects of hormonal treatment and radiotherapy (Fig. 13.15)^{9,27,31,36,37,39}

Fig. 13.15 Prostate, hormonal effect

Metaplastic squamous cells; large glycogenized cells and clusters of epithelial cells, some with enlarged nuclei. Hormonal response in confirmed prostatic adenocarcinoma (DQ, IP).

Criteria for diagnosis

♦ Squamous metaplasia,

♦ Large cells with abundant transparent cytoplasm resembling a fried egg (‘glycogen cells’),

♦ Nuclear pyknosis,

♦ Loss of nucleoli,

♦ Nuclear shrinkage,

♦ Well-preserved malignant cells may persist associated with squamous metaplasia or ‘glycogen cells’.

Transitional cell carcinoma (Figs 13.16 and 13.17)^9,37

Fig. 13.16 Transitional cell carcinoma

(A) Pleomorphic malignant cells; hyperchromatic eccentric nuclei; dense cytoplasm (tFNA of prostate; DQ, HP); (B) Corresponding tissue section of transitional cell carcinoma invading the prostate (H&E, IP).

Fig. 13.17 Combined transitional/adenocarcinoma

Aggregate of well-differentiated adenocarcinoma with nuclear crowding and microacinar pattern; adjacent group of larger, more pleomorphic malignant transitional cells (DQ, HP).

Transitional cell carcinoma may invade the prostate from the urinary bladder or it may arise from periurethral ducts within the prostate itself. Coexistence of transitional cell carcinoma and adenocarcinoma of the prostate is not rare (Fig. 13.17). It is important to distinguish transitional cell carcinoma from adenocarcinoma, since the former does not respond to hormonal treatment.

Transitional cell carcinomas involving the prostate are usually deeply invasive, high-grade tumors (see also Figs 12.29–12.31). Squamous differentiation is seen in some tumors, whereas papillary structures are rare.

Rare tumors of the prostate⁹

Cytologic descriptions and differential diagnoses of ‘foamy cell carcinoma’, prostatic ductal adenocarcinoma (papillary or endometrioid) (Fig. 13.18), mucinous (colloid), small cell carcinoma, squamous cell carcinoma (Fig. 13.19), metastatic solid tumors within the prostate, and mesenchymal tumors have been described elsewhere.⁹ The differential diagnosis between ductal cell carcinoma, prostatic adenocarcinoma and transitional cell carcinoma has been discussed. Nuclear grooves are a helpful clue for diagnosis of ductal cell carcinoma.⁴³

Fig. 13.18 Ductal cell adenocarcinoma

A papillary cluster. Notice nuclear palisading and monomorphism ( DQ, HP).

Fig. 13.19 Squamous cell carcinoma of prostate

Clusters of small malignant cells, some showing squamous differentiation including a few orangeophilic cells (center and upper left) (Pap, IP).

A morphologic and immunohistochemical study of small cell carcinomas of the prostate has been published.⁴⁴ The cytological pattern is similar to small cell tumors in other sites (Fig. 13.20). A review of adenoid cystic/basal cell carcinoma of the prostate has been reported.⁴⁵ We are not aware of any report of cytological findings of this tumor.

Fig. 13.20 Small cell (neuroendocrine) carcinoma of prostate

(A) Clusters of malignant cells with a high N : C ratio and some nuclear molding (DQ, HP); (B) Tissue section, same case (H&E, IP). Immunostaining for chromogranin was positive.

Rarely, lymphomas may involve the prostate and cause enlargement and clinical symptoms. This could be mistaken for small-cell or anaplastic carcinoma in smears. The diagnosis can be confirmed by immunostaining.

Sarcomas of the prostate are rare. These are mainly rhabdomyosarcomas in children, leiomyosarcomas (Fig. 13.21) or fibrosarcomas in adults (see Chapter 15).^9,46

Fig. 13.21 Leiomyosarcoma of prostate

Tissue fragment of moderately pleomorphic spindle cells with eosinophilic cytoplasm; some loss of cell cohesion (H&E, HP).

The place of FNA in the investigative sequence

Pathologists attempting cytological diagnosis of testicular masses must be fully conversant with the WHO classification of tumors of the testis¹² and with the bewildering patterns shown by these tumors.^12,47–49 This is also essential in the proficient identification of extragonadal germ cell tumors, primary and metastatic, in FNA samples.^50–56 FNA sampling and subsequent microscopy should ideally be performed by the same pathologist to enable cytological interpretation in the light of clinical findings.^14,18

In our hospital, after clinical examination by the urologist, the patient is referred to the clinical cytology unit. The pathologist explains the procedure and obtains a written consent from the patient. A provisional diagnosis of benign or malignant, and if malignant of seminoma versus non-seminoma, is provided to the urologist on site. The whole procedure takes less than 30 minutes. In case of malignancy, orchidectomy follows 3–7 days after diagnosis. Rapid feedback to the urologist is essential.

FNA does not replace histological diagnosis. The aim is mainly to provide a triage of cases of testicular swelling into those who do not require surgery as the first-choice treatment and those who do.¹⁴ Seminoma represents about 50% of TGCT and 40–45% of all testicular neoplasms.⁴⁸ This means that familiarity with the cytologic patterns of seminoma enables the pathologist to identify about 50% of TGCT in FNA samples.

Accuracy of diagnosis

The experience of cytologic features of germ cell tumors (GCT), primary and metastatic, accrued over two decades, permits not only a confident diagnosis of malignancy but also correct tumor typing in most cases.^14,50–66 The proper use of FNA of testicular masses reduces the need for surgery considerably.^21,58–61 Gupta et al.²⁰ underlined the role of FNA in the differential diagnosis of epididymal nodules, avoiding surgical biopsy and other investigations. See also Chapter 12 in the monograph by Linsk and Franzén,⁶⁵ and Chapter 4 in that by Zajicek.⁶⁶

Limitations of FNA of testicular tumors are:¹⁴

A few additional specific problems should be emphasized:

Complications

Fine needle aspiration may be painful in benign conditions and in fertility studies. The pain usually irradiates to the homolateral inguinal zone. It subsides in an hour and can be relieved by painkillers. FNA of malignant conditions and acute scrotum syndrome is almost painless. We have seen microscopic hemorrhage and necrosis in the subsequent surgical specimen, possibly caused by the needle, but this has never prevented histological diagnosis.

The only contraindication to testicular FNA mentioned in the literature is acute orchitis accompanied by cellulitis of the scrotum.⁶⁵

Tumor seeding in the needle track has not been recorded in a number of studies.^58,65–67 Tumor stage (TNM) was not modified following FNA in a series of malignant testicular tumors.⁶¹ In our experience of more than 120 TGCT with 5–10 years’ follow-up, there has been no evidence of dissemination caused by FNA. The benefit of a rapid and reliable diagnosis of malignancy outweighs the unproven risk of dissemination.

Technical considerations

We do not use local anesthesia for testicular FNA. Infiltration of the spermatic cord has been advocated in sequential aspirations for the evaluation of male infertility and for sperm retrieval.⁶⁸ We use 25-gauge needles, only exceptionally 23 gauge, and only one or two biopsies with one or two passes each time. US guidance may be helpful in partly cystic tumors, in non palpable US-detected lesions, in cases of retroperitoneal GCT (burnt-out TCGT), and in the follow-up of patients with lymphoma or leukemia.

Adequate training and experience in performing FNA and handling of samples is of paramount importance (see Chapter 2). Some points are of particular importance in testicular tumors. It is essential that the needle remains within the target during aspiration and that the negative pressure is released before withdrawing the needle. Smear pressure must be carefully balanced to avoid crush artifacts, particularly in seminoma. Bloody samples must be smeared quickly and are most often suboptimal.

Gross examination of the samples at smearing often gives valuable hints to the nature of the target lesion (author’s unpublished results). We strongly recommend the parallel use of DQ and Pap staining, but DQ takes preference over Pap stain. We do not use immunocytochemistry routinely in FNA of suspected testicular tumors. We believe that its use exceeds the basic aim of FNA in this field: a triage separating benign from malignant lesions. However, immunostaining for OCT 3/4, EMA, AE1/AE3, S-100, and appropriate lymphoid markers is useful to establish germ cell origin for a metastatic poorly differentiated neoplasm in a young man because of the potential for specific curative chemotherapy.⁶⁹ Immunostaining for PLAP has been used in an attempt to detect noninvasive testicular cancer in cryptorchid men.⁷⁰

The non-neoplastic testis (Figs 13.22 and 13.23)

Smears from normal testicular tissue contain cells which represent all stages of spermiogenesis, from spermatogonia to spermatozoa, in varying proportions. Spermatozoa and late spermatids are easily recognized by the nuclear size, shape and hyperchromasia, whereas the less mature forms resemble lymphoid cells of blastic type, particularly in air-dried DQ-stained smears (Fig. 13.22). Dark and pale spermatogonia can be recognized by their chromatin density, primary spermatocytes in pachytene; the latter are larger and have easily discernible thick, long chromatin threads frequently parallel to each other. Normal spermiogenesis must not be mistaken for lymphoma or TCGT. The presence of normal spermiogenesis excludes neoplasia, unless the target has been missed.

Fig. 13.22 Non-neoplastic testis

Range of spermatogenetic cells including a few mature sperms; note resemblance to lymphoid cells (DQ HP).

Fig. 13.23 Sertoli cells

Clustered cells with abundant cytoplasm, some vacuolation, and indistinct cell borders (DQ, HP).

Sertoli cells, single or in groups, are easily identified, particularly in smears from atrophic testicular tissue. Sertoli cells have pale, round nuclei, prominent nucleoli and abundant, relatively dense, vacuolated cytoplasm with indistinct borders. They often appear as naked nuclei (Fig. 13.23). Sertoli cells predominate in infancy, cryptorchidism, cirrhosis, infections and following hormonal blockage for prostate cancer. In ‘Sertoli cell only syndrome’ there is a complete absence of the germinal line; this condition cannot be distinguished from diffuse severe atrophy.

Leydig cells are difficult to recognize in FNA smears of normal testis regardless of the staining method. Nuclei are perfectly round and characteristically have one or two eccentric nucleoli. The chromatin pattern is denser than that of Sertoli cells, and the cytoplasm is better defined, dense eosinophilic and granular. Reinke’s crystals are difficult to spot except in Leydig cell tumors.⁷¹ Leydig cells predominate in aspirates from patients with Klinefelter’s syndrome. In the appropriate clinical setting, this diagnosis is suggested if smears show abundant Leydig cells and connective tissue strands and absence of cells of germ lineage.

Detailed accounts of the cytology of spermatogenesis as seen in FNA smears were published more than two decades ago.^72,73 FNA has achieved great popularity in India and Middle Eastern countries for the study of male infertility.^{21–23,74–77} It has been used to locate areas of sperm production to guide sperm extraction procedures in men with non-obstructive azoospermia.^68,78 An interesting scheme for reporting FNA testicular biopsies has been proposed by Dajani.⁷⁵ See also Linsk & Franzen⁶⁵ and Zajicek.⁶⁶

In acute orchitis.^60,65,66 the testicle is swollen and hard, and FNA is painful. Aspirates usually have abundant entangled fibrin threads, leukocytes, histiocytes, debris and fragments of necrotic seminiferous tubules. Chromatin threads may be found (Fig. 13.24).

Fig. 13.24 Acute orchitis

(A) Two intersected seminiferous tubules filled with necrotic and inflammatory cells; (B) Dirty background, naked nuclei of Sertoli cells, degenerate germinal cells (upper-right corner), tailless spermatozoa and debris (A Pap, LP; B DQ, HP).

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