Malignant giant cell tumor of the vulva.

Giant cell malignant fibrous histiocytoma or giant cell tumor of the soft parts (GCTSP) is a rare soft tissue tumor. GCTSP has an unpredictable behavior; the majority of the reported cases showed benign histology and those that showed malignant morphologic features were extremely rare. To the best of our knowledge, GCTSP has never been reported to involve the vulva in the English literature. We report the first case of malignant GCTSP of the vulva. Histologic features and the immunoprofile of the tumor and differential diagnosis are discussed in detail. Although extremely rare, consideration of the potential occurrence of GCTSP in the vulva is recommended to avoid a potential diagnostic pitfall.