Gynecomastia-like lesions in the female breast.

CONTEXT: Gynecomastia is an abnormal enlargement of the male breast, but the histopathologic abnormalities could theoretically be present in female breasts as well. To my knowledge, however, there have been no reports in the literature to date that have attributed a clinically or radiologically detectable mass in a female breast exclusively to the histopathologic findings seen in gynecomastia. OBJECTIVE: The clinical, radiologic, and histopathologic findings of 4 patients with lesions composed exclusively of the findings of gynecomastia, herein termed gynecomastia-like lesions, are presented and compared with those of 3 patients with lesser degrees of these changes, herein termed gynecomastia-like areas, which were incidental accompaniments to other lesions. SETTING: During a 26-month interval, 1242 breast excisions (excluding needle biopsies or aspirates) were examined in a 170-bed, acute-care, community-medical school teaching hospital. RESULTS: Four patients had gynecomastia-like lesions varying from 1 to 3 cm in greatest dimension with histopathologic features showing the changes of gynecomastia exclusively. Two patients had clinically palpable masses. Two other patients had masses detected only by mammography. One postmenopausal patient was taking estrogen/progesterone replacement medication. Two of the 3 others were not taking birth control pills, and none had a clinical endocrinopathy. Thus far, none of the lesions have recurred. The 3 patients with gynecomastia-like areas were diagnosed separately with infiltrating ductal carcinoma, fibroadenoma, and lipoma. CONCLUSIONS: Pathologists should be aware that clinically palpable or radiologically detected masses in female breasts may be composed exclusively of the histopathologic findings of gynecomastia.