Satellitosis and CD117 immunohistochemical expression correlates with poor outcome in thick vulvar melanoma

Melanoma of the vulva is the second most common vulvar cancer after epidermoid carcinoma. Patients suffering from this disease usually present with a late-stage disease with a poor prognosis. The prognostic factors reported in previous studies are not homogeneous and the clinical/pathogenic role of c-KIT expression is not clear. Breslow staging currently is the most accurate predictor factor.

A clinicopathological study with literature review was performed to identify predictors of prognosis and survival in melanoma of the vulva and investigated the expression of c-KIT (by immunohistochemistry) in 10 patients from the National Institute for Cancer Research (Mexico City).

The 10 patients enrolled were all older women with delayed presentation, high-stage disease and limited response to treatment. Five patients (50%) were found to have c-KIT expression; 4 of them recurred (P=0.01), and ultimately 3 died (P=0.038). We identified satellitosis and c-KIT expression as prognostic predictors for death.

We conclude that c-KIT expression is a valuable predictor of prognosis and survival, especially in thick (>4 mm) melanomas.