[Occult Breast Carcinoma and Recurrent Tumor in the Breast 14 Years after Axillary Dissection-A Case Report].

We report a patient with occult breast cancer who underwent axillary dissection as primary surgery. The patient, a 68-yearold woman, noticed a tumor measuring approximately 3 cm in diameter, in her left axilla. Biopsy of the axillary tumor revealed adenocarcinoma. Imaging studies did not detect primary lesions in the mammary gland or other organs. The patient was diagnosed with occult breast cancer and underwent axillary dissection but did not desire mastectomy or radiation therapy. The patient was closely observed thereafter. Tamoxifen was prescribed for 5 years but left breast cancer was detected 14 years after the operation. A simple mastectomy was performed. She died of respiratory failure 1 year later. Occult breast cancer may require axillary lymph node dissection and systemic therapy. Breast preservation could be an alternative treatment if followed by adequate systemic therapy and close observation.