Prepubertal gynecomastia with lobules and acini: a case report and review of the literature.

The case of an 11-year-old boy with prepubertal gynecomastia is presented. Endocrine workup, including sex steroid and pituitary hormone concentrations, as well as chromosome analysis, was normal. Microscopy of the mastectomy specimen demonstrated, in addition to ductal proliferation and fibrosis, formation of lobules and acini, simulating female breast tissue. The authors report the fourth case with this histologic feature. Review of the literature identified 41 cases of prepubertal gynecomastia; associated or underlying conditions were: adrenal adenoma or carcinoma in nine cases, testicular tumor in two, 11-beta-hydroxylase deficiency in four, familial gynecomastia in two, tuberous sclerosis in two, and, in part overlapping, sexual precocity in four. Gynecomastia usually regressed after tumor removal or cortisol replacement therapy. Histologic examination of breast tissue was performed in 18 cases. Lobule and acinus formation was described in only three.