Granular cell tumors of the breast. Steroid receptor analysis and localization of carcinoembryonic antigen, myoglobin, and S100 protein.

Granular cell tumors occur in a variety of sites, including the breast (6%). Origins from histiocytic, myogenic, fibroblastic, and neurogenic elements have been proposed. Female predominance suggests that estrogenic hormones are involved. Four granular cell tumors of the breast and one in an axillary lymph node were studied for sex steroid receptor content, myoglobin, carcinoembryonic antigen, and S100 protein localization. Antimyoglobin antibody did not localize in these tumors. Carcinoembryonic antigen and S100 protein localized in the cytoplasm of these tumors. Neither estrogen nor progesterone receptor protein were present in these tumors in detectable amounts. Ultrastructural features of these granular cell tumors in the breast are similar to those described for extramammary granular cell tumors. These studies agree with previous data that suggest a neurogenic origin for granular cell tumors.