Proliferating pilomatricoma: a subset of pilomatricoma.

Proliferating pilomatricoma is a histopathological entity that was proposed by Kaddu et al. in 1997. Proliferating pilomatricoma represents a distinctive histopathological entity; it should be differentiated from other benign and malignant neoplasms with features of hair matrix differentiation. Kaddu reported that an incompletely excised proliferating pilomatricoma may have a greater potential for local recurrence, because histopathologically it showed variable nuclear atypia and several mitotic figures. We report two patients with proliferating pilomatricoma and describe their clinical and pathological features.