Neuroendocrine carcinoma of the breast

SummaryPrimary breast neuroendocrine carcinoma (BNEC) is rare. High-grade BNEC, such as small cell carcinoma and large cell carcinoma, sometimes exhibits specific histological features, and is easily diagnosed. Low-grade solid BNEC, however, may demonstrate no specific neuroendocrine features on histological examination, which serve to distinguish it from conventional invasive carcinoma. Here, we present the case of a 46-year-old woman who was suspected of having BNEC. Suspicion was initially aroused by crush artifact during the time of frozen section. Subsequent immunohistochemistry established the diagnosis of solid BNEC according to the criteria of the WHO definition.