OBJECTIVE: Gynaecomastia is a benign proliferation of glandular tissue of the breast; however, it is an important clinical observation because it can be the first symptom of an underlying disease. Some controversy exists concerning the clinical importance of an in-depth investigation of men who develop gynaecomastia. We hypothesise that a thorough work-up is required in adult men with gynaecomastia.

DESIGN: All adult men (n = 818) referred to a secondary level andrological department at Rigshospitalet in Copenhagen, Denmark during a four-year period (2008-2011) under the diagnosis of gynaecomastia (ICD-10: N62) were included.

METHODS: Thirty-two men who did not have gynaecomastia when examined were excluded; leaving 786 men for final analyses. They underwent an andrological examination, ultrasound of the testicles and analysis of endogenous serum hormones levels.

RESULTS: In 43% of men with adult onset of gynaecomastia (≥18 years) an underlying, and often treatable, cause could be detected. In men younger at onset an underlying cause for gynaecomastia could be detected in merely 7.7%. The study is limited by the fact that we did not have access to investigate men who were referred directly by their GP to private clinics for plastic surgery or who sought cosmetic correction without consulting their GP first.

CONCLUSIONS: Our study demonstrates the importance of a thorough examination and provides a comprehensible examination strategy to disclose the underlying pathology leading to the development of gynaecomastia in adulthood.