Male axillary accessory breast cancer: A case report

RATIONALE: Accessory breast cancer is extremely rare among all cancerous diseases, especially in male patients. There were only few male axillary accessory breast cancer cases that have been reported in scientific literatures so far. Hereby, we would like to discuss a case of male axillary accessory breast cancer found in our hospital. PATIENT CONCERNS: We report a male senile patient suffering from a painful, enlarged, and hardened right axillary mass for more than 20 years. He came for further treatments due to progressive growth of the mass for 11 months with bloody ulceration for more than 1 month. DIAGNOSIS: Pathological examination manifested a grade II infiltrating ductal carcinoma derived from the accessory mammary gland (right axilla), with invasion of local skin. Immunohistochemical examination result: estrogen receptor (++) 90%, progesterone receptor (+++) 100%, human epidermal growth factor receptor-2 (1+), ki67 (20% positive), prostate specific antigen (−), caudal-related homeobox-2 (−), thyroid transcription factor-1 (−), Synaptophysin (+), NapsinA (1), and CK7 (−). INTERVENTIONS: Modified radical mastectomy and axillary lymph nodes clearance were performed on the accessary breast cancer under general anesthesia. Postoperatively, endocrine therapy was provided for the patient, orally-taken Letrozole was recommended for the rest of the patient's life. OUTCOMES: The patient recovered uneventfully and was discharged 3 days after the operation. The patient continued to take Letrozole orally regularly at home and no signs of recurrence were observed. CONCLUSION: Axillary accessory breast cancer in males is extremely rare, with no conspicuous and typical clinical presentations, which leads to inevitable neglect by clinicians. Therefore, there is significant necessity for clinicians to be cautious with this type of disease.