Fibroadenomatoid hyperplasia of the male breast.

A 69-year-old man with congestive heart failure who had been treated with digoxin for 27 years and spironolactone for 4 years developed bilateral gynecomastia. Excised tissue contained multiple nodules. Histologically, the nodules showed a structural pattern corresponding to fibroadenoma of the female breast. This lesion, called "fibroadenomatoid hyperplasia," is probably caused by treatment with spironolactone. The lesion has not previously been described in tissue from the male breast.