Multiple familial pilomatrixomas in three generations: an unusual clinical picture

Pilomatrixomas are benign cutaneous tumors derived from hair matrix cells of unclear etiology. Pilomatrixomas commonly demonstrate somatic mutations in CTNNB1, a gene coding β-catenin, a protein involved with hair follicle development. Multiple familial pilomatrixomas rarely occur and are most often associated with autosomal dominant conditions such as myotonic dystrophy and familial adenomatous polyposis (FAP). Nine families with multiple familial pilomatrixomas and no demonstrable underlying association have been reported in the literature. We present a tenth family in which five members spanning three generations grew multiple pilomatrixomas in the absence of any previously reported associations. No evidence of myotonic dystrophy, FAP, or other known associations was found. Extreme tiredness, behavioral problems, and sensory disturbances were common features across three generations but bore no temporal relation to the pilomatrixomas. The existence of a germline mutation in CTNNB1 to explain these symptoms has yet to be shown. Pilomatrixomas are potentially cutaneous markers of significant underlying pathologies. Patients presenting with multiple or familial pilomatrixomas should be thoroughly assessed for other pathologies and offered genetic screening to ensure that important diagnoses are not overlooked.