High prevalence of neuroendocrine carcinoma in breast lesions detected by the clinical symptom of bloody nipple discharge

AimBloody nipple discharge (BND) is an important clinical symptom in breast disorders, especially cancers. However, the association between this symptom and breast neuroendocrine carcinomas (NECs) has not been sufficiently investigated or well understood.MethodsWe clinicopathologically studied 89 cases using biopsy and/or resection in 144 patients who came to the hospital for a thorough examination of symptomatic BND.ResultsOf these 89 cases examined histologically, 24 (27%) were neuroendocrine carcinomas (NECs) in which >50% of cells immuno-expressed chromogranin A and/or synaptophysin. Moreover, NECs made up 44% (24/55) of the mammary cancers found because of the BND. The frequency of diagnosing malignancy preoperatively in 24 NECs was 4% by nipple discharge cytology, 40% by fine needle aspiration cytology, 62% by core needle biopsy and 67% by mammotome biopsy. There were neither postoperative recurrences nor metastases in the NEC cases during a mean follow-up of 83.7 months. The 24 NECs were subclassified into neuroendocrine ductal carcinoma in situ (NE-DCIS) (9 cases) and microinvasive (7 cases) and invasive (8 cases) NECs with extensive NE-DCIS components. Most NECs had early-stage and low-grade pathological parameters: pTis or pT1 (96%), pN0 (96%), low nuclear grade (83%), absence of necrosis (88%), immuno-positivity of estrogen and progesterone receptors (100%) and absence of HER2 protein overexpression (100%).ConclusionsNECs predominantly with NE-DCIS lesions, often under-diagnosed preoperatively, accounted for an important share of breast conditions associated with BND. It is, therefore, worth keeping this type of breast cancer in mind when performing medical examinations on patients with BND.