Primary Breast Carcinoid With Metastasis and Ectopic Acth Secretion: A Diagnostic Dilemma

Abstract: Carcinoid tumors most frequently develop in the gastrointestinal tract but have been described in many organs of the body. Primary neuroendocrine carcinoma of the breast is rare-only 31 cases have been reported in literature. Immunohistochemical examination showing expression of chromogranin and/or synaptophysin confirms evidence of neuroendocrine differentiation. In primary neuroendocrine carcinoma of the breast, more than 50% of the cell population shows neuroendocrine differentiation. Foci of neuroendocrine differentiation usually can be seen in breast carcinoma and are reported to be present in about 2% to 5% of breast cancer cases. Carcinoid tumor metastatic to the liver from the breast is very unusual. We report a case in which the patient underwent breast lumpectomy with axillary dissection. The tumor initially was diagnosed as an infiltrative lobular carcinoma with axillary lymph node metastasis. Re-examination of the breast tumor histopathology, however, proved it to be a primary carcinoid tumor.