A giant axillary mass treated as breast cancer metastasis
A 69-year-old woman with a giant fist-sized left axillary mass was admitted to the Dermatology Department of Kawasaki Medical School. No primary tumor was identified, and she was referred to the Department of Breast and Thyroid Surgery of Kawasaki Medical School Hospital. A 90-mm tumor was found in the left axilla, which exhibited ulceration and infection. Imaging analysis revealed no abnormalities in the breast or other organs such as the lungs. Needle biopsy revealed a poorly differentiated carcinoma exhibiting a mixture of glandular structures and keratinization, and it was difficult to determine the original tumor. The differential diagnoses were primary skin cancer, including adnexal organs, occult breast cancer, accessory breast cancer and metastatic tumor from unknown malignancy. Immunohistochemical analysis revealed that this tumor had no estrogen receptor, progesterone receptor or human epidermal growth factor receptor 2 expression. Primary chemotherapy was initiated because the National Cancer Comprehensive Network guidelines recommend that unclassified axillary epithelial malignancies in women be treated as occult breast cancer. After 4 cycles of epirubicin plus cyclophosphamide followed by 4 cycles of docetaxel plus doxifluridine, the axillary tumor shrunk to 15 mm in size. Axillary lymph node dissection, including skin resection of the axilla, was performed, and radiotherapy to the left breast and left axilla/supraclavicular lymph node area was administered. There has been no recurrence for over 4 years.