Granular cell myoblastoma, whether a misnomer or not, is a well-established entity of the medical literature. It occurs widely in the body. Its occurrence in the breast, though infrequent, is of great significance because of its clinical similarity to carcinoma. Only rarely a correct diagnosis is made clinically. Histological diagnosis is easy though diagnosis in a frozen section has been found to be simple by some1 and not so easy by others.2 Knowledge of the tumor and experience is thus important in avoiding errors in diagnosis.
About 6% of granular cell myoblastomas occur in the breast.3 A review of the literature has revealed 49 documented cases (Table). The present paper reports three additional cases which illustrate some of the difficulties involved in the diagnosis.
Report of Cases
Case 1.—A 55-year-old Negro laundress was admitted to the Philadelphia General Hospital on Feb 23, 1965, with a mass in the