Endocrinology and metabolism: Edited by Allen W. RootGynecomastia in prepubertal and pubertal menMa, Nina Sa; Geffner, Mitchell Ea,bAuthor Information aDivision of Endocrinology, Diabetes, and Metabolism, Children's Hospital Los Angeles, USA bThe Saban Research Institute, Los Angeles, California, USA Correspondence to Nina S. Ma, MD, Division of Endocrinology, Diabetes, and Metabolism, Children's Hospital Los Angeles, 4650 Sunset Boulevard, Mailstop 61, Los Angeles, CA 90027, USA Tel: +1 323 361 7695; fax: +1 323 361 8152; e-mail: firstname.lastname@example.org Current Opinion in Pediatrics: August 2008 - Volume 20 - Issue 4 - p 465-470 doi: 10.1097/MOP.0b013e328305e415 Buy Metrics Abstract Purpose of review Gynecomastia is often benign, but it can be the sign of serious endocrine disease and the source of significant embarrassment and psychological stress. Understanding its pathogenesis is crucial to distinguish a normal developmental variant from pathological causes. Recent findings There is a growing list of potential causes of gynecomastia. Rare and unique case reports continue to supplement the literature to augment our understanding of this common physical finding. However, the exact basis for the pathogenesis of gynecomastia remains unknown. There appears to be a local imbalance between estrogen stimulation and the inhibitory action of androgens on breast tissue proliferation. Gynecomastia in a prepubertal boy is rare and should prompt an immediate evaluation for possible endocrine disorder. Pubertal gynecomastia, on the contrary, is common and usually physiological, with sympathetic reassurance and watchful waiting the mainstays of treatment. There is some evidence that early pharmacological intervention with antiestrogens may diminish persistent pubertal gynecomastia, but treatment with an aromatase inhibitor has not been shown to be more effective than placebo. Summary Treatment of gynecomastia is geared toward its specific cause. Currently, there are insufficient data to recommend medical therapy in children with idiopathic gynecomastia. © 2008 Lippincott Williams & Wilkins, Inc.