Neurofibromatosis: A cause of prepubertal gynecomastia

BACKGROUND: Atypical presentations of gynecomastia not associated with obesity are often underappreciated. Unilateral manifestation, prepubertal onset, and a history of associated disorders may contribute to a unique clinical presentation for which the diagnosis and management may remain uncertain. This report reviews neurofibromatosis as a cause for atypical presentation of gynecomastia in prepubertal boys to help establish guidelines for diagnosis and management. METHODS: Six nonobese male patients (body mass index ≤20) had an onset of gynecomastia at younger than 9 years and were referred for evaluation between June of 1994 and December of 2006. RESULTS: The median age of onset of breast enlargement was 71/2 years (range, 4 to 8 years). Three had bilateral involvement, four had localized involvement of the nipple-areola complex, and two had diffusely involved breast tissue. Five of the six patients were African American (compared with 20 percent for classic gynecomastia). Median postoperative follow-up was 7 years, and all were followed beyond puberty. No recurrences were seen, although one patient developed a metachronous lesion in the contralateral breast. No patient had an abnormal endocrine metabolic workup. CONCLUSIONS: Atypical gynecomastia may present in the prepubertal boy and appears more prevalent in African Americans. For neurofibromatosis, it is more likely unilateral, can be localized to the nipple-areola complex, or entails diffuse breast involvement. An endocrine workup appears to be noncontributory.