Malignant melanoma of the vulva: a clinical-pathologic review of 16 cases

Abstract

A study of 16 malignant melanomas of the vulva was undertaken to identify the histologic variants found on the vulva and to evaluate the use of microstaging as a predictor of behavior. Ten of 16 cases were melanoma of mucous membrane (MMM) type of acral lentiginous melanoma. This percentage (63%) is notably higher than in previous reports. Three cases were nodular melanoma (NM). All lesions of MMM and NM type occurred on mucous membranes. Three cases were superficial spreading melanoma and all occurred on skin. Neurotropism was observed in 5 of the 10 MMM. Neurotropic melanoma has been reported only once previously in the vulva. Depth of the melanomas was greater than 1.0 mm in 13 of the 16 cases. This correlated with Clark and Chung levels of 3 or higher in the same 13 cases. A poor outcome with an overall 5 year survival of 20% of cases with invasive disease was found. The poor outcome and large number of thick lesions would suggest a correlation, but the distribution is skewed and number of cases too small for statistical documentation.