Vulva, vagina & female urethra

Melanocytic lesions

Pigmented lesions

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PubMed Search: Pigmented vulvar lesions

Priya Nagarajan, M.D., Ph.D.
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Cite this page: Nagarajan P. Pigmented lesions. website. Accessed March 30th, 2023.
Definition / general
  • This topic covers common nonmelamoma pigmented lesions of vulva
Case reports
Clinical images

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Hyperpigmented brownish macules

Angiokeratoma of Fordyce

Microscopic (histologic) images

Contributed by Priya Nagarajan, M.D., Ph.D.


Dysplastic nevus with mild atypia

Dysplastic nevus with moderate atypia

Dysplastic nevus with severe atypia

Mucosal melanotic macule

Mucosal melanotic macule, melanocytic cocktail (HMB45, MART1, tyrosinase)

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Dowling-Degos disease

Angiokeratoma of Fordyce

Differential diagnosis
  • Acanthosis nigricans (Indian J Dermatol 2011;56:678, Fertil Steril 1993;59:583)
    • Clinical presentation:
      • Pigmented / brown velvety plaques
    • Histologic features:
      • Mild epidermal acanthosis, papillomatosis (usually with elongated, delicate papillae), hyperkeratosis, horn pseudocysts
      • Mild increase in basal layer pigmentation

  • Angiokeratoma (Eur J Gynaecol Oncol 2011;32:597, Acta Dermatovenerol Croat 2010;18:271)
    • Clinical presentation:
      • Dark papules and nodules
    • Histologic features:
      • Epidermal hyperkeratosis, acanthosis (often irregular) and low papillomatosis in close proximity to thin walled dilated blood vessels filled with red blood cells in papillary dermis

  • Dowling-Degos disease (Ann Dermatol 2011;23:205)
    • Clinical presentation:
      • Multiple symmetric pigmented papules
    • Histologic features:
      • Elongation and prominent pigmentation of epidermal rete ridges
      • No increase in melanocyte density
      • Suprapapillary plate thinning, pigment incontinence and hyperkeratosis may be present

  • Genital dysplastic nevi
    • Clinical presentation:
      • Irregular pigmented lesion, often on labia majora
    • Histologic features:
      • Features overlap with atypical genital nevi (J Cutan Pathol 2008;35:24, Am J Surg Pathol 2008;32:51)
      • More lentiginous spread and elongation of rete ridges may be seen
      • Lamellar eosinophilic fibroplasia of papillary dermis is present
      • Variable amounts of lymphohistiocytic inflammatory infiltrate may be present

  • Genital melanocytic nevi (Eur J Gynaecol Oncol 2002;23:323, J Cutan Pathol 2008;35:889, Dermatology 2010;221:55, Dermatol Online J 2010;16:9)
    • May affect about 2% of women
    • Any type of nevus can be seen in the vulva
    • Clinical presentation:
      • Irregular pigmented lesion up to 1 cm in size
      • Lesions typically involve labia minora, labia majora or mucosal aspect of clitoris
    • Histologic features:
      • Some degree of architectural disorder is allowed in special sites such as vulva
      • Nevi may be junctional or compound and may be asymmetrical
      • Junctional component is composed frequently of lentiginous proliferation of melanocytes, which is often nested
      • Nests may be large with retraction artifact and usually arise from the sides of rete ridges and may involve the suprapapillary plate
      • Adnexal extension may be seen
      • Dermal melanocytes mature with dermal descent
      • Overlying epidermis may be hyperplastic
      • Due to frequent irritation, features of trauma such as focal pagetoid spread of melanocytes, pigmented parakeratosis and transepidermal elimination of melanocytic nests may be seen

  • Genital melanosis (J Reprod Med 1993;38:5, Am J Dermatopathol 1985;7:51)
    • Clinical presentation:
      • Variably extensive and slowly developing pigmentation
    • Histologic features:
      • Hyperpigmentation of basal keratinocytes
      • Melanocyte density is usually normal or very mildly increased
      • Pigment incontinence in superficial dermis may be present

  • Lichen simplex chronicus (Dermatol Clin 2010;28:669)
    • Clinical presentation:
      • Dark, pigmented, thickened skin
    • Histologic features:
      • Epidermal acanthosis (may be slightly irregular), hyperkeratosis (often with presence of stratum lucidum), hypergranulosis
      • Fibrosis or presence of thickened, vertically oriented collagen fibers in papillary dermis
      • Superficial perivascular lymphohistiocytic infiltrate
      • Pigment incontinence may be present

  • Mucosal melanotic macules (J Am Acad Dermatol 2000;42:640, J Am Acad Dermatol 2014;70:e81)
    • Clinical presentation:
      • Dark asymmetrical macules
    • Histologic features:
      • Hyperpigmentation of basal keratinocytes
      • Melanocyte density is usually normal or very mildly increased
      • No nested or confluent proliferation of melanocytes

  • Normal vulvar pigmentation
    • When compared to the rest of the body, genital skin is usually more pigmented
    • Histologically, it is common to see at least some amount of melanin pigmentation within the basal keratinocytes
    • Therefore, it is important to know the baseline pigmentation of the patient, since the presence of basal keratinocytic pigmentation can be misleading, especially in small biopsies

  • Pigmented basal cell carcinoma (Dermatol Online J 2011;17:8, Acta Dermatovenerol Alp Pannonica Adriat 2011;20:81)

  • Pigmented condyloma acuminatum (J Dermatol 2014;41:337, J Dermatol 2012;39:860)
    • Clinical presentation:
      • Dark warty growths with fleshy or filiform appearance
      • Often multiple
    • Histologic features:
      • Epidermal acanthosis with hyperkeratosis and at least focal parakeratosis, with an undulating surface
      • Deep aspect of the lesion is fairly regular and sharply demarcated
      • Superficial keratinocytes with perinuclear halo, hyperchromatic nuclei and irregular / wrinkled nuclear contours (koilocytes), consistent with human papilloma viral cytopathic effect

  • Pigmented seborrheic keratosis (Clin Exp Dermatol 2005;30:17)
    • Clinical presentation:
      • Often multiple
      • Dark, brown papules or nodules with a stuck on appearance
    • Histologic features:
      • Epidermal acanthosis, low papillomatosis, hyperkeratosis and horn pseudocysts

  • Pigmented vulvar intraepithelial neoplasia / pigmented bowenoid papulosis (Gynecol Oncol 1980;10:201, An Bras Dermatol 2014;89:825, J Am Acad Dermatol 2010;62:597)
    • Clinical presentation:
      • Dark plaques, papules
    • Histologic features:
      • Usual type vulvar intraepithelial neoplasia (squamous cell carcinoma in situ or Bowen disease) with full thickness keratinocytic atypia
      • Melanin pigment often in small dense clusters within the epithelium
      • Pigment incontinence may be present
      • Lichenoid lymphohistiocytic inflammatory infiltrate may be present

  • Postinflammatory pigmentary alteration (Dermatol Ther 2010;23:449)
    • Clinical presentation:
      • Slowly increasing pigmentation which is often the result of an inflammatory condition
      • Initiating inflammatory disease is frequently asymptomatic
    • Histologic features:
      • Prominent pigment incontinence with melanin lying free in the superficial dermis or more frequently, increased numbers of pigmented melanophages
Additional references
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