PILOMATRIX CARCINOMA AND MULTIPLE PILOMATRIXOMAS

Pilomatrixoma is the only skin appendage tumour showing predominantly hair matrix differentiation. Rarely, aggressive or malignant variants are reported in the literature. We report a case of a 44-year-old male with multiple pilomatrixomas, one of which grew rapidly, recurring se veral times. Histological examination of this tumour showed predominan tly hair matrix differentiation but also abortive hair follicle format ion with pilar keratinization reminiscent of a trichoepithelioma. Nume rous mitoses and moderate cellular pleomorphism were present, associat ed with infiltration of subcutaneous skeletal muscle and vascular inva sion.