Pilomatrical Carcinosarcoma of the Cheek with Subsequent Pulmonary Metastases

We report a case of malignant pilomatrixoma with a pronounced biphenotypic morphology. The lesion, which was excised from the cheek of a 36-year-old man, was composed of a large pilomatrixoma lying within a spindled, sarcomatoid stroma. Fourteen months later, the tumor metastasized to the right upper lobe of the lung. We describe the tumor's pathology, histology, and immunochemistry and discuss the differential diagnosis. We also speculate on its histogenesis.