Carcinoid Tumor of Breast

The so-called carcinoid tumor of the breast is synonymous with invasive ductal carcinoma with neuroendocrine differentiation. The tumor cells are arranged in small and large nests separated by fibrovascular tissue. The clinical presentation, gross features, and behavior are no different from the ordinary breast carcinoma. The presence of estrogen receptors, patterns of metastases, and occasional presence of an in-situ component further support the notion that the so-called carcinoid tumor of the breast and ductal carcinoma are related lesions.