Breast lymphoma is an uncommon neoplasm affecting the breast and is extremely rare in males. While gynaecomastia is common and in most cases benign, it can sometimes result from significant pathology and the physician should keep in mind the possible diseases that can lead to gynaecomastia. This paper reports a case of lymphoma presenting as unilateral gynaecomastia. The paper discusses the differential diagnosis and emphasises the points that should raise the suspicion of pathology.Mammography, high resolution ultrasound and biopsy findings are discussed and literature survey is presented.