Pilomatrix carcinoma of the clitoris.

Pilomatrix carcinoma, a malignant counterpart of pilomatrixoma, is a rare skin neoplasm composed of basaloid and shadow cells that characterize differentiation toward the hair matrix. The authors present a case of pilomatrix carcinoma of the clitoris, a very unusual location not previously reported. Diagnostic criteria and differential diagnoses are discussed. Pilomatrix carcinoma should be differentiated from benign pilomatrixoma and other carcinomas with shadow cells, including basal cell carcinoma with matrical differentiation and metastases of visceral carcinomas with shadow cells.