THE OCCURRENCE of granular cell myoblastoma of the breast is rare. Haagensen and Stout,1 in 1946, reported five cases in the breast and found only five previous reports of this growth in the breast in the world literature. Colberg and Hubay,2 in 1952, gathered 27 cases of breast granular cell myoblastoma from the world literature which comprised 6% of these growths reported in all areas of the body. Stein,3 in 1963, unearthed 31 cases in the literature and reported 4 of his own. Although one case of familial nature has been reported,4 this is not a feature of this tumor.
Granular cell myoblastoma has been regarded generally as arising from striated muscle as originally expounded by Abrikossoff5 in 1926. However, these tumors occur frequently where there is no striated muscle such as in the gum of the newborn. The breast has no striated muscle although