Metastatic primary neuroendocrine carcinoma of the breast (NECB)

Neuroendocrine carcinoma of the breast (NECB) is a subtype of breast cancer. The diagnostic criteria of primary NECB were established in 2003 and updated in 2012. It is a rare entity, and few studies have reported the histogenesis, immunohistochemistry for a pathological diagnosis, clinical behavior, therapeutic strategies, and the prognostic factors. Because of the rarity of this disease, consistent diagnostic criteria will remind physicians of this disease when making a differential diagnosis to enable a timely diagnosis and prompt treatment. Herein, we report a case of primary NECB who presented with a history of right hip pain arising from an osteolytic lesion in the right acetabulum and ischium. The course of investigation started with metastasis in the right hip and concluded with a diagnosis of NECB. In addition to the case report, we also conducted a literature review.