Features of pigmented vulval lesions on dermoscopy

Background: The dermoscopic criteria for benign and malignant lesions on the vulva are not well established due to the lack of large series of such lesions. Melanoma should always be included in the differential diagnosis of pigmented lesions on the vulva especially when they are wide, or of recent onset. Elsewhere on the skin dermoscopy plays an important role in the selection of suspicious pigmented lesions, as well as in the selection of the best site to perform the biopsy.

Objectives: To analyse the dermoscopic patterns observed in pigmented lesions of the vulva.

Methods: We analysed a nonselected consecutive series of 68 histopathologically proven cases comprising five melanomas, 16 naevi, 20 lentigos, 12 benign vulval melanoses, 11 cases of postinflammatory pigmentation, three pigmented cases of usual vulval intraepithelial neoplasia (VIN) and one seborrhoeic keratosis seen at our institution. The dermoscope was covered by translucent disposable food wrap and/or antibacterial gel to prevent possible transmission of infections. Descriptive statistics were performed using multiple correspondence analysis.

Results: The parallel (37%), ring-like (9%), homogeneous (22%), globular-like (13%) and reticular-like (6%) patterns were observed on benign lesions (naevi, lentigo, vulval melanosis and postinflammatory pigmentation). The cerebriform pattern (6%) was observed only on VIN and seborrhoeic keratosis. The multicomponent pattern (6%) was associated with melanoma (60%). In cases of melanoma we also occasionally observed an irregular pattern, a whitish or blue-whitish veil, irregularly distributed dots and globules and atypical vascular pattern. Using multiple correspondence analysis, we designed a new algorithm for the early detection of vulval melanomas.

Conclusions: Dermoscopy can play a role in the noninvasive classification of vulval melanosis. However, further studies of larger collaborative series are needed to validate our vulval melanoma diagnostic algorithm. VIN and seborrhoeic keratosis share the same dermoscopic features and biopsy should be considered for seborrhoeic-like keratosis. In case of doubt pathological examination of a biopsy remains mandatory.