Schwannoma of the breast: a case report and review of the literature.

Schwannoma arising within breast parenchyma is very rare. This report describes such a case in a 58-year-old woman. The tumor, which measured 4.4 x 3.5 x 2.1 cm, was painless, mobile and elastic-soft. Mammography showed a well-circumscribed, oval-shaped nodule without microcalcifications. At ultrasonography it appeared as a hypoechoic solid mass. Fine-needle cytology revealed several clusters of spindle cells indicative of a neoplasm of mesenchymal origin. Histological examination evidenced the characteristic morphological appearance of a schwannoma with Antoni A and Antoni B areas. A review of the 23 proven cases of breast schwannoma is included. The main differential diagnostic findings are also discussed.