Pilomatricoma is a benign skin tumor derived from the hair follicle, usually located in the head and neck and presenting in the first two decades of life. Clinically it most commonly presents as a hard, mobile, well circumscribed nodule. Microscopically it is characterized by the presence of shadow cells and may show calcification, while extensive ossification is rare. Surgical removal is the treatment of choice, as the recurrence rate is very low. We present a rare case of late regressive pilomatricoma of the arm in a 33 year old female which presented with extensive ossification.