Vulva and Vagina

1.1 VESTIBULAR PAPILLOMATOSIS (HYMENAL TAG) VS. CONDYLOMA ACUMINATUM

	Vestibular Papillomatosis (Hymenal Tag)	Condyloma Acuminatum
Age	Young women of reproductive age, upon onset of sexual activity	Adults and sexually active adolescents; peak age 20-39 years
Location	Vaginal vestibulum, inner aspects of the labia minora	Vulva, mucosal and skin surfaces, vagina, less commonly cervix
Symptoms	Generally asymptomatic, symptoms can be related to irritation, secondary infection, and local trauma, occasionally dyspareunia	Generally asymptomatic, symptoms can be related to irritation and local trauma
Signs	Incidental finding during speculum exam: delicate, skin or mucosa colored, nearly translucent, finger-like, filiform projections in small clusters, some in linear arrangement, often symmetrical	Papillary, verrucous, or warty lesions and cauliflower-like projections fused at the base; often multiple or multifocal; no symmetry in distribution
Etiology	Unknown; considered a normal anatomical variant of the vulva	Low-risk human papillomavirus infection, most commonly implicated viral types 6 and 11
Histology	1. Branching “villiform” papillae (Fig. 1.1.1)	1. Verrucous/warty architecture; at nonkeratinized site, papillae can appear delicate (Fig. 1.1.5)
	2. Normal-appearing, nonkeratinizing squamous epithelium (Fig. 1.1.2)	2. Broad papillary fronds with pointed or rounded ends; hyperkeratosis and parakeratosis
	3. Papillae can appear fused in tangential sections (Fig. 1.1.3)	3. Papillae are often fused at the base
	4. No atypia/viral cytopathic effect, small hyperchromatic nuclei (Fig. 1.1.4)	4. Viral cytopathic changes/koilocytosis; enlarged hyperchromatic nuclei with irregular contours surrounded by cytoplasmic halo (Figs. 1.1.6 and 1.1.7)
Special studies	• None required	• None required
	• Absence of low-risk HPV by in situ hybridization	• HPV in situ hybridization for low-risk HPV can be done for confirmation
	• Ki-67 proliferative activity limited to the parabasal epithelial layers	• Ki-67 proliferative activity can be increased with scattered cells labeled in the upper epithelial layers (Fig. 1.1.8)
Treatment	None required; lesions causing symptoms can be removed	Can regress spontaneously; conservative excision, immunomodulating topical agents can be used for large persisting lesions
Prognosis	Unremarkable	Benign; however, recurrences are common even after spontaneous regression

Figure 1.1.1 Vestibular papillomatosis. Multiple branching delicate villiform papillae.

Figure 1.1.2 Vestibular papillomatosis. Same case as Figure 1.1.1, higher magnification. Vestibular papilloma. Delicate papillae are lined by normal nonkeratinizing squamous epithelium. No hyperkeratosis is seen.

Figure 1.1.3 Vestibular papillomatosis. Coalescing papillae with thin fibrovascular cores.

Figure 1.1.4 Vestibular papillomatosis. Squamous epithelium without viral cytopathic change (koilocytosis).

Figure 1.1.5 Condyloma acuminatum. Verrucous lesion with multiple papillary projections lined by nonkeratinizing squamous epithelium.

Figure 1.1.6 Condyloma acuminatum. Rounded papillae with some degree of hyperkeratosis and parakeratosis. Occasional atypical, binucleate cells are present.

Figure 1.1.7 Condyloma acuminatum. Same case as Figure 1.1.5, higher magnification. Koilocytes: large cells with abundant cytoplasm, typical perinuclear halo, and enlarged hyperchromatic nuclei with irregular contours.

Figure 1.1.8 Same case as Figure 1.1.5. Condyloma acuminatum. Increased Ki-67 labeling in midzone and superficial epithelial layers.

1.2 CONDYLOMA ACUMINATUM VS. SQUAMOUS PAPILLOMA

	Condyloma Acuminatum	Squamous Papilloma
Age	Adults and sexually active adolescents; peak age 20-39 years	Reproductive age and postmenopausal women
Location	Vulva, mucosal and skin surfaces, vagina, less commonly cervix	Vagina, vulva, less commonly cervix
Symptoms	Generally asymptomatic; symptoms can be related to irritation and local trauma	Usually asymptomatic; symptoms can be related to irritation and local trauma
Signs	Papillary, verrucous, or warty lesions and cauliflower-like projections fused at the base; often multiple/multifocal	Polypoid growth, single or multiple
Etiology	Low-risk human papillomavirus infection, most commonly implicated viral types 6 and 11	Considered normal anatomic variant
Histology	1. Verrucous/warty architecture; multiple papillae are often fused at the base (Fig. 1.2.1)	1. Polypoid lesion with central fibrovascular core (Figs. 1.2.5 1.2.6, 1.2.7)
	2. Broad papillary fronds with pointed or rounded ends (Fig. 1.2.2)	2. No significant arborization; rounded contour (Fig. 1.2.6)
	3. Mature squamous epithelium	3. Mature squamous epithelial lining
	4. Hyperkeratosis, hypergranulosis (Fig. 1.2.3)	4. Depending on the location, hyperkeratosis can be variably present; hypergranulosis is not typical
	5. Koilocytosis is seen at least focally, often in the creases between the papillae (Fig. 1.2.4) Also see Sections 1.1 and 1.3	5. No cytologic atypia, koilocytosis (Fig. 1.2.8)
Special studies	• None	• None
	• HPV in situ hybridization for low-risk HPV can be done for confirmation	• No evidence of HPV by in situ hybridization
	• Ki-67 proliferative activity is increased with scattered positive cells in the upper epithelial layers (see Fig. 1.1.8)	• No increase in Ki-67 labeling above the parabasal areas
Treatment	Can regress spontaneously; conservative excision, laser fulguration, or immunomodulating topical agents for persisting lesions	None required; diagnostic biopsy is usually curative
Prognosis	Benign; however, recurrences are common even after spontaneous regression	Unremarkable

Figure 1.2.1 Condyloma acuminatum. Verrucous lesion with multiple papillary projections with pointed or rounded ends.

Figure 1.2.2 Condyloma acuminatum. Same case as Figure 1.2.1, higher magnification.

Figure 1.2.3 Condyloma acuminatum. Same case as Figure 1.2.1, higher magnification. Marked hyperkeratosis.

Figure 1.2.4 Condyloma acuminatum. At least focal viral cytopathic change (koilocytes) is seen in the creases between the papillae.

Figure 1.2.5 Squamous papilloma. Polypoid lesion with central fibrovascular core.

Figure 1.2.6 Squamous papilloma. Same case as in Figure 1.2.5. Minimal arborization is present.

Figure 1.2.7 Squamous papilloma. Single polypoid lesion with fibrovascular core and rounded end.

Figure 1.2.8 Squamous papilloma. Same case as in Figure 1.2.5, higher magnification. Mature squamous epithelium lacking cytologic atypia.

1.3 CONDYLOMA ACUMINATUM VS. SEBORRHEIC KERATOSIS

	Condyloma Acuminatum	Seborrheic Keratosis
Age	Adults and sexually active adolescents; peak age 20-39 years	Middle-aged and postmenopausal women
Location	Vulva, vagina, skin, and mucosal surface	Vulvar skin (keratinized portions)
Symptoms	Often asymptomatic, some present with pruritus, irritation	Often asymptomatic, some present with pruritus, irritation
Signs	Cauliflower-like lesion(s), skin colored or white	Papular lesion(s), waxy skin colored, or pigmented with stuck-on appearance, often multiple
Etiology	Low-risk HPV, HPV types 6 and 11 are most common	Generally is not associated with HPV; some report association with HPV 6/11 in isolated cases
Histology	1. Complex verrucous architecture (Fig. 1.3.1)	1. Polypoid or papillary architecture is not uncommon (Fig. 1.3.3)
	2. Acanthosis, elongation, and thickening of rete ridges	2. Epithelial hyperplasia, acanthosis; invaginations of the epithelial surface with flattened base (Fig. 1.3.4); pseudohorn cysts (Fig. 1.3.5); squamous eddies and mitosis in irritated seborrheic keratosis
	3. Compact hyperkeratosis, hypergranulosis	3. Laminated hyperkeratosis; hypergranulosis is minimal or absent
	4. Epithelial maturation is preserved; koilocytosis is seen at least focally (Fig. 1.3.2) Also see Figs. 1.2.1 1.2.2, 1.2.3, 1.2.4, 1.6.5, and 1.6.6	4. Expansion of small monomorphic basophilic keratinocytes without viral cytopathic change (koilocytosis) (Fig. 1.3.6)
Special studies	• In situ hybridization for HPV 6/11, positive diffuse nuclear signal	• Usually, no detectable HPV by in situ hybridization
	• Increased Ki-67 labeling in upper epithelial layers	• Increased Ki-67 labeling
Treatment	Can regress spontaneously; conservative excision, laser fulguration, or topical immunomodulating agents can be used for persistent lesions	None required; shave biopsy is often curative, and large lesions causing discomfort can be removed via local excision or laser fulguration
Prognosis	Benign; however, recurrences are common even after spontaneous regression	Unremarkable

Figure 1.3.1 Condyloma acuminatum. Verrucous architecture with multiple papillary projections.

Figure 1.3.2 Condyloma acuminatum. Hyperkeratosis, hypergranulosis, and preserved squamous maturation. Koilocytes are seen in the superficial epithelial layers.

Figure 1.3.3 Seborrheic keratosis with polypoid architecture.

Figure 1.3.4 Seborrheic keratosis. Marked acanthosis with anastomosing rete ridges.

Figure 1.3.5 Seborrheic keratosis. Same case as Figure 1.3.3, higher magnification. Pseudohorn cyst.

Figure 1.3.6 Seborrheic keratosis. Proliferation of monotonous small basophilic keratinocytes. Lack of atypia/koilocytosis.

1.4 CONDYLOMA ACUMINATUM VS. VERRUCA VULGARIS (COMMON WART)

	Condyloma Acuminatum	Verruca Vulgaris (Common Wart)
Age	Adults and sexually active adolescents; peak age 20-39 years	Children, including infants, and adolescents; can be seen in adults. Girls are more commonly affected than boys
Location	Vulva, mucosal and skin surfaces, as well as vagina and cervix	Vulva, perineum; also on the hands/fingers, toes, knees
Symptoms	Generally asymptomatic, symptoms can be related to irritation and local trauma	Generally asymptomatic, symptoms can be related to irritation and local trauma
Signs	Papillary, verrucous, or sessile lesions; can turn white after application of acetic acid; often multiple; in children raises concern for sexual abuse	Rough keratotic papules
Etiology	Low-risk HPV infection; viral types 6 and 11 cause 90% of lesions	HPV infection; viral types 2 and 4 cause majority of the lesions
Histology	1. Complex branching architecture, usually asymmetrical (Fig. 1.4.1)	1. Warty architecture with some degree of symmetry; peripheral rete ridges pointing toward the center of the lesion (Fig. 1.4.3)
	2. Rounded and pointed papillary projections; acanthosis, elongation and thickening of rete ridges, irregular or flattened lesion base	2. Pointed ends of filiform papillae
	3. Hyperkeratosis	3. Hyper- and parakeratosis (Fig. 1.4.4)
	4. Hypergranulosis is present, but not as prominent as in verruca	4. Hypergranulosis; variation is size and shape of keratohyalin granules (Fig. 1.4.5)
	5. Koilocytosis at least focally seen, often in the creases between the papillae (Fig. 1.4.2) Also see Figs. 1.2.1 1.2.2, 1.2.3, 1.2.4	5. Koilocytotic atypia absent or very focal (Fig. 1.4.6)
Special studies	• In situ hybridization for HPV 6/11, diffuse nuclear signals	• Generally not needed
	• Ki-67 proliferative activity can be increased in upper epithelial layers	• HPV typing can be considered in medicolegal cases
Treatment	Can regress spontaneously; conservative excision, laser fulguration, or topical immunomodulating agents can be used for persistent lesions	Biopsy is often curative; for extensive or persistent lesions, topical agents, cryotherapy, laser, and surgical excision can be used
Prognosis	Benign; however, recurrences are common even after spontaneous regression	Benign, usually resolve spontaneously with time. Do not raise suspicion for sexual abuse when present on the vulva of female infants and young girls

Figure 1.4.1 Condyloma acuminatum. Verrucous lesion with multiple papillary projections with pointed or rounded ends. Broad-based lesion with no apparent symmetry.

Figure 1.4.2 Condyloma acuminatum. Same case as Figure 1.4.1, higher magnification. Prominent koilocytosis.

Figure 1.4.3 Verruca vulgaris. Symmetrical lesion with peripheral rete ridges pointing toward the center of the lesion. Mature squamous epithelium with marked hyperkeratosis.

Figure 1.4.4 Verruca vulgaris. Same case as in Figure 1.4.3, higher magnification. Filiform papillae with marked hyper- and parakeratosis.

Figure 1.4.5 Verruca vulgaris. Same case as in Figure 1.4.3, higher magnification. Prominent hypergranulosis and thick compact hyperkeratosis.

Figure 1.4.6 Verruca vulgaris. Same case as in Figure 1.4.3, higher magnification. Very focal koilocytotic change can be seen.

1.5 VERRUCOUS CARCINOMA VS. CONDYLOMA ACUMINATUM

	Verrucous Carcinoma	Condyloma Acuminatum
Age	Postmenopausal women	Adults and sexually active adolescents; peak age 20-39 years
Location	Vulva, uncommonly cervix	Vulva, vagina, less commonly cervix
Symptoms	Vulvar mass, symptoms related to secondary infection and local trauma	Related to local irritation and trauma
Signs	Broad-based exophytic vulvar mass	Exophytic papillomatous lesion
Etiology	Unknown; some cases reportedly are associated with HPV 6; vulvar acanthosis with altered differentiation (VAAD) has been suggested as putative precursor	Low-risk HPV, most commonly types 6 and 11
Histology	1. Downward invasive growth pattern with some exophytic component (Figs. 1.5.1 1.5.2, 1.5.3, 1.5.4)	1. Exophytic growth; complex branching architecture (Fig. 1.5.7)
	2. Prominent acanthosis, expansion of rete ridges, and compression of dermal papillae; lack of true fibrovascular cores (Fig. 1.5.3)	2. Acanthosis, elongation, and thickening of rete ridges; “spire-like” papillary projections
	3. Broad epithelial nests, pushing-border invasion (Fig. 1.5.4)	3. Base of the lesion can be flat or irregular due to tangential orientation; no invasion
	4. Hyperkeratosis can be seen; hypergranulosis is not typical	4. Hyperkeratosis and hypergranulosis
	5. Bland cytologic features, lack of overt viral epithelial changes (Fig. 1.5.5)	5. Koilocytosis at least focally seen, often in the creases between the papillae (Fig. 1.5.8)
	6. Inflammatory infiltrate with eosinophils in the stroma (Fig. 1.5.6)	6. Stromal inflammation is not typical Also see Figs. 1.1.6 1.1.7, 1.1.8 and 1.2.1 1.2.2, 1.2.3, 1.2.4
Special studies	• None helpful in this differential	• None helpful in this differential
	• Presence of low-risk HPV does not preclude the diagnosis	• In situ hybridization for low-risk HPV can be considered
Treatment	Wide/radical local excision; radiation therapy can be considered for advanced and recurrent tumors	Conservative excision may be necessary in large lesions
Prognosis	Locally invasive tumor; regional lymph node involvement and distant metastases are rare	Benign; morbidity is related to local irritation, trauma, and secondary infection

Figure 1.5.1 Verrucous carcinoma. Pale lesion with verrucous architecture and “pushing-border” stromal invasion.

Figure 1.5.2 Verrucous carcinoma. Same case as in Figure 1.5.1.

Figure 1.5.3 Verrucous carcinoma. Same case as in Figure 1.5.1, surface. Mature bland squamous epithelium with surface hyperkeratosis.

Figure 1.5.4 Verrucous carcinoma. Same case as in Figure 1.5.1, higher magnification. Broad epithelial nests extend into the stroma.

Figure 1.5.5 Verrucous carcinoma. Same case as in Figure 1.5.1, higher magnification. Mature keratinocytes lacking cytologic atypia.

Figure 1.5.6 Verrucous carcinoma. Stromal inflammatory infiltrate with eosinophils is seen at the deep edge.

Figure 1.5.7 Condyloma acuminatum. Exophytic lesion with warty architecture; prominent acanthosis.

Figure 1.5.8 Condyloma acuminatum. Koilocytosis is seen on the surface of the lesion.

1.6 HIGH-GRADE SQUAMOUS INTRAEPITHELIAL LESION (HSIL, VIN 2-3) WITH CONDYLOMATOUS FEATURES VS. CONDYLOMA ACUMINATUM

	High-Grade Squamous Intraepithelial Lesion (HSIL, VIN 2-3) with Condylomatous Features	Condyloma Acuminatum
Age	Adults; peak age 45-50 years	Adults and sexually active adolescents; peak age 20-39 years
Location	Vulva	Vulva, vagina
Symptoms	Related to irritation, local trauma or underlying immunosuppressive condition	Related to irritation or local trauma
Signs	Warty/papillomatous lesion	Warty/papillomatous lesion
Etiology	High-risk HPV infection, types 16 and 18 are most common; frequently in immunocompromised patients	Low-risk HPV infection, types 6 and 11 are most common
Histology	1. Epithelial immaturity (Figs. 1.6.1 and 1.6.2)	1. Retained epithelial maturation (Fig. 1.6.7)
	2. Minimal or absent koilocytosis; significant cytologic squamous atypia throughout epithelial thickness (Figs. 1.6.3 and 1.6.4)	2. Cytologic atypia is limited to superficial epithelial layers/koilocytes (Fig. 1.6.8)
	3. Mitotic figures in the upper epithelial layers (Fig. 1.6.5)	3. Mitotic figures are infrequent; if present, observed exclusively in parabasal layers
Special studies	• p16, strong and diffuse (Fig. 1.6.6, left)	• p16 patchy or negative
	• Ki-67 labeling increased in upper epithelial layers (Fig. 1.6.6, right)	• Ki-67 labels individual cells in upper epithelial layers
	• In situ hybridization positive for high-risk HPV	• In situ hybridization positive for low-risk HPV; high-risk HPV not detected
Treatment	Local excision	Conservative excision may be necessary in large lesions
Prognosis	Considered a precursor of HPV-related squamous cell carcinoma; can progress to invasive carcinoma if not removed	Benign; morbidity is related to local irritation, trauma, and secondary infection

Figure 1.6.1 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Lesion with wart-like architecture appears “blue,” immature at low power.

Figure 1.6.2 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Same case as in Figure 1.6.1, higher magnification. Full-thickness epithelial immaturity.

Figure 1.6.3 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Same case as in Figure 1.6.1, higher magnification. Epithelial immaturity and notable cytologic atypia.

Figure 1.6.4 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Hyperchromasia and atypia throughout epithelial thickness.

Figure 1.6.5 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Mitotic figures in the mid-zone and upper epithelial layers.

Figure 1.6.6 High-grade squamous intraepithelial lesion (HSIL/VIN 2-3) with prominent condylomatous architecture. Same case as in Figure 1.6.1. Diffuse p16 expression in at least lower one-third of the epithelial thickness (left); markedly increased Ki-67 labeling throughout epithelial thickness (right).

Figure 1.6.7 Condyloma acuminatum. Verrucous lesion with multiple papillary projections with pointed or rounded ends.

Figure 1.6.8 Condyloma acuminatum. Same case as Figure 1.6.7, higher magnification. Preserved epithelial maturation. Focal koilocytosis on the surface.

1.7 HIGH-GRADE SQUAMOUS INTRAEPITHELIAL LESION (HSIL, VIN 2-3) VS. BENIGN SQUAMOUS EPITHELIUM (VULVAR SKIN)

	High-Grade Squamous Intraepithelial Lesion (HSIL, VIN 2-3)	Benign Squamous Epithelium (Vulvar Skin)
Age	Adults; peak age 45-50 years	N/A
Location	Vulva	Vulva
Symptoms	Often asymptomatic	N/A
Signs	Papule, plaque; can be raised pale, pigmented, or red	Usually none; pigmentation or keratotic plaque can be seen; frequently in vulvar excisions with adjacent HSIL or invasive squamous cell carcinoma
Etiology	High-risk HPV infection, most commonly HPV type 16	N/A
Histology	1. Epithelial thickening; acanthosis is often seen	1. Epithelial thickening; acanthosis may be seen
	2. Hyperchromatic/basophilic-appearing epithelium at low power (Figs. 1.7.1 1.7.2, 1.7.3)	2. Blue/basophilic-appearing epithelium (Figs. 1.7.8 and 1.7.9)
	3. Immature cell expansion and disorganization in parabasal zone	3. Quiescent parabasal zone; can appear expanded if tangentially sectioned (Fig. 1.7.10)
	4. Surface maturation is often preserved; hyperkeratosis is often present (Figs. 1.7.4 and 1.7.5)	4. Preserved epithelial maturation; hyperkeratosis is usually not prominent
	5. Enlarged, hyperchromatic nuclei with nuclear contour irregularities pointing in different directions; nucleoli are typically not seen (Fig. 1.7.6)	5. Uniform normal size nuclei with small nucleoli and smooth nuclear membranes (Fig. 1.7.11); occasional atypical multinucleated cells can be seen in the epithelium
	6. Mitoses are common and extend above the parabasal zone	6. Mitoses are rare; in parabasal zone, if present
Special studies	• Strong and diffuse expression of p16 (block-like), at least 1/3 of the epithelial thickness (Fig. 1.7.7, left)	• Negative or weak, focal p16 staining (Fig. 1.7.12, left)
	• Increased Ki-67 labeling in the upper epithelial layers (Fig. 1.7.7, right)	• Ki-67 labeling is limited to basal parabasal layers (Fig. 1.7.12, right)
Treatment	Local excision, laser evaporation	None required
Prognosis	Considered a precursor of HPV-related squamous cell carcinoma; can progress to invasive carcinoma if not removed	Unremarkable

Figure 1.7.1 High-grade squamous intraepithelial lesion (high-grade VIN). Acanthosis, broadening of the rete ridges.

Figure 1.7.2 High-grade squamous intraepithelial lesion (high-grade VIN). Hyperchromatic/basophilic epithelium with acanthosis and broadening of the rete ridges.

Figure 1.7.3 Focal high-grade squamous intraepithelial lesion (high-grade VIN). Expanded parabasal zone (center).

Figure 1.7.4 High-grade squamous intraepithelial lesion (high-grade VIN). Same case as in Figure 1.7.1, higher magnification. Expansion of parabasal zone. Maturation is preserved in upper epithelial layers.

Figure 1.7.5 High-grade squamous intraepithelial lesion (high-grade VIN). Same case as in Figure 1.7.2, higher magnification. Loss of epithelial maturation; however, granular and corneal layers are still present.

Figure 1.7.6 High-grade squamous intraepithelial lesion (high-grade VIN). Same case as in Figure 1.7.3, higher magnification. Expansion of the parabasal zone, atypical keratinocytes with increased nucleocytoplasmic ratio, and frequent mitotic figures above the parabasal zone.

Figure 1.7.7 High-grade squamous intraepithelial lesion (high-grade VIN). Same case as in Figure 1.7.1. Diffuse “block-like” expression of p16 in at least two-thirds of epithelial thickness (left) and increased Ki-67 labeling above the parabasal layers (right).

Figure 1.7.8 Normal (nonlesional) skin adjacent to HSIL in a vulvar excision specimen. Acanthosis, broadening of the rete ridges, and hyperkeratosis.

Figure 1.7.9 Normal (nonlesional) skin adjacent to HSIL in a vulvar excision specimen. Acanthosis, broadening of the rete ridges, and basophilic-appearing epithelium.

Figure 1.7.10 Normal (nonlesional) skin near the margin in a vulvar excision for squamous cell carcinoma. Parabasal zone appears expanded due to tangential sectioning; no cytologic atypia is seen.

Figure 1.7.11 Normal (nonlesional) skin. Same case as in Figure 1.7.9, higher magnification. Normal epithelial maturation; keratinocytes lack cytologic atypia.

Figure 1.7.12 Normal (nonlesional) skin adjacent to HSIL in a vulvar excision specimen. Same case as in Figure 1.7.8. No expression of p16 (left) and low Ki-67 proliferative activity limited to parabasal zone (right).

1.8 DIFFERENTIATED-TYPE VULVAR INTRAEPITHELIAL NEOPLASIA (HIGH-GRADE VIN, SIMPLEX TYPE) VS. REACTIVE/REPARATIVE ATYPIA

	Differentiated-Type Vulvar Intraepithelial Neoplasia (High-Grade VIN, Simplex Type)	Reactive/Reparative Atypia
Age	Adults, postmenopausal, usually sixth to eighth decade	Adults, no specific age predilection
Location	Vulva	Vulva
Symptoms	Vulvar irritation and itching	Vulvar irritation and itching
Signs	Lichen sclerosus-like appearance, inflammatory/dermatitis-like changes, no distinct lesional borders	Erythematous skin, appearance of dermatitis; adjacent erosion/ulceration can be seen
Etiology	Unknown; TP53 mutation may be implicated	Related to the underlying condition
Histology	1. Elongation and anastomosis or thickening of rete ridges (Figs. 1.8.1 and 1.8.2); dermal or interface inflammation can be present	1. Acanthosis is common; hyperkeratosis can be seen; dermal/interface inflammation (Fig. 1.8.8)
	2. Variable hyperkeratosis; prominent intercellular bridges (Fig. 1.8.3)	2. Variable hyperkeratosis; intercellular bridges can be seen in cases with intraepithelial inflammation, but generally not prominent (Fig. 1.8.9)
	3. Abnormal keratinization, abundant eosinophilic cytoplasm in the basal and parabasal epithelial layers (Figs. 1.8.4 and 1.8.5)	3. No abnormal keratinization/cytoplasmic eosinophilia
	4. Marked nuclear atypia in basal/parabasal layers, dyskeratotic keratinocytes (Fig. 1.8.6)	4. Enlarged relatively uniform vesicular nuclei with inconspicuous nucleoli (Fig. 1.8.10)
	5. Ulceration can be occasionally seen, particularly in cases with adjacent invasive carcinoma	5. Epithelial attenuation at the edge of an ulcer with surface exudate (Fig. 1.8.11)
	6. Background of lichen sclerosus-type changes can be seen	6. Association with lichen sclerosus is not consistent
Special studies	• Strong p53 expression in keratinocytes nuclei extending to the middle epithelial layers can be seen in some cases (Fig. 1.8.7, left)	• p53 labeling usually limited to the basal layers (Fig. 1.8.12, left)
	• Variable Ki-67 proliferative activity (Fig. 1.8.7, right)	• Some increase in Ki-67 proliferative activity can be observed (Fig. 1.8.12, right)
Treatment	Local excision with clear margins	Treatment of the underlying cause (fungal, bacterial infection, etc.)
Prognosis	Considered a precursor of non-HPV-related vulvar squamous cell carcinoma; quick progression to invasive carcinoma	Benign; prognosis related to the underlying condition

Figure 1.8.1 Differentiated vulvar intraepithelial neoplasia (simplex VIN). Prominent acanthosis and hyperkeratosis.

Figure 1.8.2 Differentiated vulvar intraepithelial neoplasia. Elongated anastomosing rete ridges.

Figure 1.8.3 Differentiated vulvar intraepithelial neoplasia. Thickened rete ridges; prominent intercellular bridges. Parabasal zone appears disorganized.

Figure 1.8.4 Differentiated vulvar intraepithelial neoplasia. Same case as in Figure 1.8.1, higher magnification. Atypical parabasal keratinocytes with prominent nucleoli. Cytoplasmic hypereosinophilia (right).

Figure 1.8.5 Differentiated vulvar intraepithelial neoplasia. Atypical parabasal keratinocytes with cytoplasmic keratinization (hypereosinophilia).

Figure 1.8.6 Differentiated vulvar intraepithelial neoplasia. Basal and parabasal atypia and brisk mitotic activity.

Figure 1.8.7 Differentiated vulvar intraepithelial neoplasia. Same case as in Figure 1.8.1. Increased p53 labeling (left) and only mildly increased Ki-67 proliferative activity (right).

Figure 1.8.8 Vulvar skin with reactive changes at the edge of erosion. Interface and dermal mixed inflammatory infiltrate.

Figure 1.8.9 Vulvar skin with reactive changes. Neutrophils in the epidermis. Notable intercellular bridges. Nuclear enlargement and some degree of pleomorphism in the middle epithelial layers.

Figure 1.8.10 Vulvar skin with reactive changes at the edge of erosion. Same case as in Figure 1.8.8, higher magnification. Keratinocytes with uniform enlarged nuclei and inconspicuous nucleoli.

Figure 1.8.11 Vulvar skin with reactive changes at the edge of an ulcer. Basal and parabasal hyperchromasia, but no significant atypia.

Figure 1.8.12 Vulvar skin with reactive changes at the edge of erosion. Same case as in Figure 1.8.8. Rare cells in basal/parabasal layers staining for p53 (left) and mild increase in Ki-67 labeling (right).

1.9 BASAL CELL CARCINOMA VS. BASALOID SQUAMOUS CELL CARCINOMA

	Basal Cell Carcinoma	Basaloid Squamous Cell Carcinoma
Age	Adults over 40 years of age	Adults, peak incidence sixth decade
Location	Vulva	Vulva
Symptoms	Vulvar irritation, pruritus, ulcer	Vulvar irritation and/or mass
Signs	Raised nodule or ulcerated lesion, slow growing; can be pigmented	Vulvar mass or raised plaque, occasionally ulcerated
Etiology	Cutaneous lesions are associated with significant UV exposure; etiology of vulvar BCC is unclear. Mutations in PTCH gene may be implicated	High-risk HPV infection; HPV 16 is the most commonly implicated viral type. Risk factors include immunosuppression and smoking
Histology	1. Overlying epidermis is typically unremarkable; basaloid nests are contiguous with the basal layer (Figs. 1.9.1 1.9.2, 1.9.3)	1. Associated high-grade squamous intraepithelial lesion (HSIL, vulvar intraepithelial neoplasia 3 [VIN 3]) in the majority of cases
	2. Stromal clefting and loose/myxoid stroma; necrosis is not common	2. Stromal desmoplasia; stromal clefting can be seen but less frequent; necrosis can be seen (Figs. 1.9.7 and 1.9.8)
	3. Squamoid-appearing areas can be seen, but overt keratinization is usually absent	3. Overt squamous differentiation and keratinization in the middle of the invasive nests (Fig. 1.9.9)
	4. Consistent peripheral palisading (Fig. 1.9.4)	4. Peripheral palisading can be seen but not a consistent feature
	5. Monotonous elongated hyperchromatic nuclei and clear cytoplasm (Fig. 1.9.5)	5. Enlarged hyperchromatic atypical nuclei with at least some degree of pleomorphism; dense eosinophilic cytoplasm
	6. Mitotic activity can be brisk accompanied by variable number of apoptotic bodies	6. Frequent mitosis; apoptotic bodies can be seen
Special studies	• BerEP4 positive (Fig. 1.9.6, left)	• Negative or focal BerEP4 (Fig. 1.9.10, right)
	• p16 patchy/negative (Fig. 1.9.6, right)	• p16 strong and diffuse (Fig. 1.9.10, left)
	• No detection of high-risk HPV by in situ hybridization	• High-risk HPV detected by in situ hybridization
Treatment	Conservative excision with clear margins	Wide/radical local excision; regional lymph node dissection in cases with the depth of invasion > 1 mm
Prognosis	Local recurrences are uncommon; lymph node metastases are exceedingly rare	Recurrences (local or in regional lymph nodes) in up to 24% of cases; lymph node metastases in up to 15% of cases with the depth of invasion > 1 mm

Figure 1.9.1 Basal cell carcinoma. Nodular growth pattern with epidermal connection. Loose stroma surrounding the nests.

Figure 1.9.2 Basal cell carcinoma. Irregular epithelial nests in the stroma with focal epithelial connection and peripheral clefting. Overlying epidermis is uninvolved.