Male breast cancer (MBC) is a rare condition in the spectrum of breast cancer. It is most commonly diagnosed in men between the ages of 60 and 70, with an average age of 67 at diagnosis. MBC accounts for less than 1% of all breast cancer cases, with incidence varying across ethnic groups. Rates are highest among non-Hispanic Black men (1.89 per 100,000). Elevated incidence in South and Central Africa may be linked to hyperestrogenism from liver infections. Occult male breast cancer is extremely rare, accounting for only 0.3%–1% of all cases of breast cancer. Genetic predispositions, especially BRCA2 mutations, significantly increase the risk of MBC greater than BRCA1 mutations. The most frequent histological type is infiltrating ductal carcinoma, while invasive lobular carcinoma is exceptionally uncommon. MBC tumours are typically hormone receptor-positive. Key risk factors for MBC include older age, black ethnicity, genetic mutations, family history, liver cirrhosis, and testicular disorders. Most patients present with painless breast lumps, and about 50% have lymph node involvement at diagnosis. A 61-year-old male presented with a 6-year history of non-tender swelling in the left axilla, with no associated systemic symptoms. Clinical examination revealed matted, erythematous lymph nodes, prompting fine needle aspiration and subsequent excision biopsy. Cytology demonstrated markedly atypical tumour cells with a high N: C ratio and significant pleomorphism. Histopathology of the lymph node confirmed effaced architecture with malignant cells arranged in sheets, cords, and cohesive tumour nests, along with capsular invasion. Immunohistochemistry showed CK7 and GATA3 positivity and strong HER2 (3+) expression, while ER, PR, Mammaglobin, and CK20 were negative—findings consistent with metastatic HER2-positive primary breast carcinoma. Positron emission tomography imaging revealed metabolically active axillary and deep pectoral nodes. The patient received neoadjuvant chemotherapy with docetaxel, carboplatin, trastuzumab, and filgrastim, followed by modified radical mastectomy with the breast parenchyma showing ypT0, ypN1a post 4 cycles of NACT. This case highlights the diagnostic challenges of male breast cancer, particularly when presenting solely as axillary lymphadenopathy. Immunohistochemistry and positron emission tomography play an essential role in establishing diagnosis and staging. Timely neoadjuvant chemotherapy and surgery achieved primary tumour clearance, underscoring the importance of early suspicion, comprehensive evaluation, and guideline-based management of HER2-positive MBC.
Akhtar et al. (2026) studied this question.