Neuroendocrine carcinoma of the breast - a pilot study of a Danish population of 240 breast cancer patients

Neuroendocrine carcinoma of the breast - a very recent diagnosis, which was not recognized by WHO until 2003 - has lately been the subject of increasing attention. It is defined as a primary breast cancer with morphologic features similar to other types of neuroendocrine tumors of the lung and gastrointestinal tract combined with positive neuroendocrine immunohistochemical markers. While much information has been gathered during the last decade, most studies suffer from poor statistics due to a low incidence, and there are still fundamental open questions regarding etiology and prognosis. Furthermore, apparent limitations of the WHO definition appear to influence diagnosis. Here, we present our own results obtained from 13 cases and furthermore review previous reports with particular reference to incidence, clinical, histological, and prognostic features.