Author(s): Niedermeyer HP, Peris K, Hfler H
BACKGROUND: The malignant variant of pilomatrixoma is pilomatrix carcinoma, a low-grade, malignant lesion with a tendency to recur. Only three cases with visceral metastases, occurring some years after primary diagnosis, have been reported. METHODS: A case of metastatic pilomatrix carcinoma of the neck in a patient, age 50 years, is presented. RESULTS: Histologic examination of the cutaneous lesion showed a dense infiltrate of basaloid cells, an abrupt transition to shadow cells, and central necrosis. Two months after primary diagnosis, pulmonary and brain metastases developed. Despite chemotherapy and irradiation, the patient died a widespread disease 18 months after the primary diagnosis. An autopsy confirmed the diagnosis of pilomatrix carcinoma with metastases to several organs including the heart, lung, brain, liver, pancreas, kidney, adrenal gland, gastric and colorectal submucosa, skin, and bone. CONCLUSIONS: Pilomatrix carcinoma is very rare and usually behaves like a low-grade, malignant lesion with a tendency to recur. This patient's tumor is unique because of its highly aggressive behavior and visceral metastases.