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5 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Neuroendocrine neoplasms of the breast are rare breast cancers whose cells make hormone-like granules, ranging from slow-growing tumours to small cell carcinoma like that of the lung. They are easily mistaken for ordinary breast cancer or for spread from elsewhere; slow-growing forms are treated like hormone-driven breast cancer and small cell forms with the lung small cell regimens.
The 2019 WHO classification divides neuroendocrine neoplasms of the breast into well-differentiated neuroendocrine tumour, neuroendocrine carcinoma (small cell and large cell) and, separately, invasive carcinomas of other types with neuroendocrine differentiation such as solid papillary and hypercellular mucinous carcinoma (Tan 2020). The entity as first defined by the WHO in 2012 spans well-differentiated tumours to highly aggressive small cell carcinomas; correct diagnosis needs an interdisciplinary approach because the tumours are misclassified as carcinoma with neuroendocrine differentiation, no special type carcinoma or a metastasis to the breast, and in one specialised unit only five of 612 neuroendocrine patients had a breast primary (Cancers 2020). Primary small cell neuroendocrine carcinoma of the breast is histologically indistinguishable from the lung tumour, so a primary elsewhere must be excluded, and there is no standard approach to treatment because only a limited number of cases have been reported (Int J Surg Case Rep 2017).
How it differs from its parent: the well-differentiated tumours are usually hormone-receptor positive and behave like luminal breast cancer, whereas the small cell carcinomas are treated with the platinum-etoposide regimens of small cell lung cancer rather than the breast pathways; neither has a trial of its own.
| Setting | Approach | Guideline |
|---|---|---|
| Well-differentiated tumour | Treated as HR-positive breast cancer. | not mapped |
| Small cell or large cell neuroendocrine carcinoma | Surgery and the extrapulmonary neuroendocrine carcinoma pathway (platinum and etoposide, radiotherapy); no standard exists. | not mapped |