engleski

Primary Neuroendocrine Carcinoma of the Breast: A Diagnostic Approach to the Special Type of Breast Malignancy

Introduction: WHO classification from 2003 defines primary neuroendocrine carcinomas (NEC) of the breast as a group of tumors with expression of neuroendocrine markers in more than 50% of tumor cells. In the current WHO classification this category is renamed to “carcinomas with neuroendocrine features” without defined clear-cut of the percentage of tumor cells positive for neuroendocrine markers. Aim(s): To evaluate diagnostic criteria for primary breast NEC. Materials and methods: Histopathologic reports of patients with breast carcinoma in the last 10 years were analyzed ; cases of breast NEC were selected and reviewed for the positivity for neuroendocrine markers, estrogen receptors (ER), progesterone receptors (PR), HER-2/neu and presence of in situ component. Results: Among 11034 cases of breast carcinoma, 37 primary NEC (incidence rate: 0.3%), and 3 metastatic NEC were identified. Synaptophysin was diffusely positive in 35 (94.6%), chromogranin-A in 32 (86.5%) and NSE in 21 (56.6%). 34 (91.9%) were ER+ ; 32 (86.5%) PR+ ; 3 cases (8.1%) were triple-negative and only one case was HER-2/neu positive. Five out of seven reported cases had ductal carcinoma in situ (CIS) component. Conclusion: Breast NEC is a rare tumor. Positivity for synaptophysin and chromogranin-A is evident in the majority of primary breast NEC. Metastatis must be ruled out to declare it primary. Helpful characteristics for accurate diagnosis are presence of CIS, ER and PR positivity.

breast cancer, special types, carcinoma with neuroendocrine features, neuroendocrine markers

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