RESUMEN
A 37-year-old woman was admitted to our hospital because of cervical and axillary lymphadenopathy that developed after delivery. An axillary lymph node biopsy revealed metastatic adenocarcinoma. Immunohistochemical staining indicated that the tumor cells expressed c-ErbB-2, but were negative for the estrogen and progesterone receptors. No definite evidence of breast cancer was detected. The patient underwent chemotherapy for suspected metastatic breast cancer. She complained of swelling in the left breast 22 months later, and a biopsy showed invasive ductal carcinoma. Here, we report a case of hormone receptor-negative occult breast cancer in a patient with cervical and axillary lymphadenopathy presenting as a cancer with an unknown primary site.