Clinical overview
Pigmentary disorders of the vulva are common but under-taught. They are clinically important not because they are dangerous (most are not) but because: (1) they cause significant distress and stigma when visible; (2) they can be mistaken for sinister diagnoses such as VIN or melanoma if the registrar does not recognise their pathology; (3) some require biopsy to exclude malignancy. This chapter describes the pathological features of the main pigmentary disorders of the vulva and adjacent skin — vitiligo, albinism, post-inflammatory hyperpigmentation, lentigo, melanotic macules, melanoma, and the related entity of intertrigo (an inflammatory dermatosis with secondary pigmentary changes).
Core knowledge
Vitiligo
Vitiligo destroys melanocytes, while albinism preserves melanocytes but reduces melanin production.
Pathology:
- Autoimmune destruction of melanocytes in the epidermal basal layer.
- Complete absence of melanocytes in fully developed lesions.
- T-cell mediated; associated with other autoimmune diseases (thyroid, type 1 diabetes, alopecia areata).
- Wood's lamp shows enhanced demarcation.
Clinical correlate:
- Sharply demarcated milky-white patches with no pigment.
- Symmetric, often peri-orificial (vulva, mouth, eyes, axilla, perianal).
- Asymptomatic; no scaling, no itch.
- May koebnerise — develop at sites of trauma.
Management: topical steroids or calcineurin inhibitors; phototherapy (narrowband UVB) where access permits; cosmetic camouflage; psychological support.
Albinism (oculocutaneous)
Pathology:
- Genetic disorder of melanin synthesis (TYR, OCA1; OCA2 mutation in southern African populations highest prevalence globally — ~1:3,900 in some communities).
- Melanocytes present but produce little or no melanin.
- Affects skin, hair, eyes.
Clinical correlate:
- Diffuse hypopigmentation of skin, hair, and irides.
- Increased susceptibility to UV damage and squamous cell carcinoma (substantial issue in South Africa).
- Vulval skin is similarly hypopigmented; standard gynaecological care plus sun protection advice for non-vulval skin.