breast cancer, occult cancer, axillary nodal metastasis
We report a case of a 56-year-old woman with occult breast cancer (OBC) who presented with a hard metastatic mass in the left axilla, but no breast mass was palpable. Biopsy of the lymph node was performed and histological examination identified a metastatic ductal carcinoma poorly differentiated. Immunohistochemistry showed that the resected lymph node was positive for both estrogen and progesterone receptor. No pathological findings were obtained through mammography, ultrasonography and MRI of both breasts. Systemic examinations (CT, endoscopy) releaved no extramammary primary lesions. All these data suggested an OBC and a left modified radical mastectomy was performed. Pathological examination failed to find the primary cancer lesion on the removed specimen. The patient was treated with adjuvant chemotherapy and hormonal therapy and she presents no evidence of disease 4 years after surgery.