Gynaecomastia can be detected in between one-third and two-thirds of men. A wide variety of causes of gynaecomastia, some physiological, some very serious, have been identified. We present a case in which the cause of the gynaecomastia seemed obvious after history taking and physical examination but we finally ended up with a more complex combination of diagnoses. This case stresses the importance of combining history taking and physical examination with additional laboratory testing for the assessment of gynaecomastia.