Pigmented lesions of the vulva: histological features

The vulva is an anatomical and histological combination of cutaneous and mucous components. It is the site of various pigmented lesions, in 10 to 12% of white women, often of unknown etiology. The clinical features are polymorph, non-specific, thus requiring a biopsy. Histological analysis helps to rule out the diagnosis of melanoma, which frequently leads to mutilating surgical treatment and which has an unfavorable prognosis. We present a review of the anatomical and histological characteristics of the normal vulva and of the process of melanogenesis. In addition, the histological criteria that enable the etiological diagnosis of vulvar pigmented lesions are presented. Some of these lesions are tumoral, melanocytic or non-melanocytic, isolated or related to a general pathology; others, non-tumoral, related to inflammatory, immunological, hormonal, or paraneoplasic mechanisms, can be manifestations of systemic diseases. Biopsy specimen analysis and anatomo-clinical correlation are essential for the appropriate diagnosis and the treatment of these lesions.