Sarcomatoid pilomatrix carcinoma.

Pilomatrix (pilomatrical) carcinoma is a rare cutaneous adnexal tumor with matrical differentiation and recurrent and metastatic potential. Sarcomatoid pilomatrix carcinoma is a rare variant which shows a sarcomatoid component intermingling with the epithelial one. There are only 4 cases previously published. We present an additional case on the hand of a 78 year-old man which appeared as a 6 mm hyperkeratotic, focally ulcerated plaque. A shave biopsy demonstrated a dermal infiltrative neoplasm, composed of markedly atypical-appearing basaloid cells with focal necrotic/ghost cells, as well as an intimately associated population of atypical oval to spindle-shaped cells. Both the epithelial and the sarcomatoid components expressed cytokeratins (CKs) AE1/AE3, CK 5/6 and CAM 5.2, as well as beta-catenin and LEF-1. The tumor failed to express CK7, CK20, S100, thyroid transcription factor 1 (TTF1), CDX2, prostate-specific antigen (PSA) and CD34. The tumor was completely excised with Mohs surgery, and there has been no recurrence in the 8 months of follow-up to date.