Pilomatrixoma of the adult male breast: a rare tumor with typical ultrasound features

Abstract

Pilomatrixomas are uncommon benign skin neoplasms arising from the hair follicle matrix. They occur more commonly in children than adults. Most originate on the head, neck, or upper extremities, less commonly on the trunk or lower extremities, and very infrequently in the breast. We present a rare case of pilomatrixoma of the breast in an adult male. As the patient had a strong family history of breast cancer, a full work-up of the breast mass was performed. Ultimately, an excisional biopsy was carried out for patient reassurance.

Keywords: Breast; male; pilomatrixoma; ultrasound.

Figure 1

Mediolateral oblique view of mammogram demonstrates a small well-circumscribed oval mass just underneath a radiopaque skin marker in the medial right breast near the nipple. The mass contains multiple small punctuate calcifications.

Figure 2

A gray-scale ultrasound image of the lesion shows a well-defined isoechoic oval mass, parallel with the skin measuring 7 mm × 3.5 mm, containing the small hyperechoic foci of calcification observed on the mammogram.

Figure 3

Typical basaloid and shadow cells of pilomatrixoma (Hemotoxylin and eosin, 10×).

Figure 4

A well-circumscribed breast lesion on gray-scale ultrasound parallel to the skin surface has not been biopsied but is likely to be benign given its stability on sonography for nearly two years.