BACKGROUND Carcinoma of the breast infrequently presents initially as axillary adenopathy. In such cases, after biopsy proves the presence of metastatic carcinoma, the primary tumor generally is assumed to be in the ipsilateral breast, despite negative mammographic findings and the lack of a clinically palpable breast mass. METHODS The authors recently studied a case of a 50-year-old woman in whom recurrent neuroendocrine carcinoma of the breast presented as a contralateral axillary lymph node metastasis. After mastectomy ipsilateral to the metastasis proved negative for tumor, a histologic comparison of the previous contralateral tumor with that in the lymph node was performed, followed by biopsy of the clinically and mammographically negative original lumpectomy site. RESULTS Histologic and immunohistochemical studies proved that the original, metastatic, and locally recurrent tumors were identical, sharing unusual neuroendocrine features. The patient is currently disease free after chemotherapy. CONCLUSION Contralateral mammary carcinoma should be considered in the workup of a patient who presents with evidence of an axillary lymph node metastasis. Locally recurrent breast carcinoma may be clinically and mammographically occult. Histologic review of prior biopsy material and comparison with current tissue is essential in proper patient management.