Clinical and histopathologic spectrum of pilomatricomas in adults

Pilomatricomas are benign cutaneous neoplasms with differentiation toward hair matrix. Although previously reported to occur mostly in children and young adults, Taaffe et al. recently observed a second onset peak in adults and the elderly.

To study the clinical and histopathologic features of pilomatricomas in adults we analyzed files and histologic sections of all cases of pilomatricomas seen at the Department of Dermatology, University of Graz, Graz, Austria, between January 1980 and December 1990.

A total of 118 patients were identified, 58 of whom were > 45 years of age. The clinical features of patients > 45 years of age were generally similar to those of patients < 45 years of age. Differential diagnoses in both groups were also comparable except in some cases of the older study-group where differential diagnoses included basal cell carcinoma, keratoacanthoma, and metastasis. Recurrence of the lesions after simple excision was observed in one patient > 45 years of age. Histopathologically, lesions in both age groups showed similar features except in four lesions of the older patients where "atypical" features were present. The histopathologic differential diagnosis of the lesions with "atypical" features included pilomatrical carcinoma, basal cell carcinoma with matrical differentiation, and matricoma.

Our study reveals the relatively frequent occurrence of pilomatricomas in adults and the elderly. Pilomatricoma should be considered along with other benign and malignant conditions in the clinical differential diagnosis of solitary, firm skin nodules presenting in adults and the elderly, especially on the head and neck.