Vulvar Neurilemmoma at the Labium Minus

Neurilemmoma is a benign slow-growing nerve sheath neoplasm that is rarely found in the female genital system. To date, thirteen cases of vulvar neurilemmoma have been reported in the world literature. We report here on the first Korean case of vulvar neurilemmoma. A 43-year-old woman presented with a 0.6×0.6 cm sized oval nodule at the left labium minus. Complete excision was done. Microscopically, the mass was a well circumscribed lesion that was alternatively composed of cellular Antoni A and paucicellular Antoni B areas; The Antoni A areas were composed of spindle cells with twisted, buckled nuclei and occasional intranuclear vacuoles, and the spindle cells were arranged in short bundles or fascicles. Immunohistochemically, the spindle cells were positive for S100 protein and negative for desmin. Although it has a very low incidence, neurilemmoma should be considered in the differential diagnosis of a cutaneous or subcutaneous mass in the vulva.