Breast lumps in men: four case reports and a literature review.

Four cases of men who consulted their family physicians because of breast lumps are reported. Their final diagnoses were as follows: intraductal carcinoma, gynecomastia, seminoma, and lipoma. A review of the literature revealed a lack of data on the prevalence of breast lumps among male adults, considerable ambiguity in clinical definitions of the term "gynecomastia," and a general uncertainty about the prevalence of malignancy in such lesions. Further epidemiologic studies are needed to determine the true prevalence and nature of breast lumps in men.