Fine needle aspiration cytology of breast carcinoma with neuroendocrine features--a case report with histopathological and immunohistochemical correlation.

Cytohistological and immunohistochemical features of a rare case of breast carcinoma with diffuse neuroendocrine features occurring in an elderly female patient is reported. Cytology demonstrated predominantly single and loose clusters of monomorphic plasmacytoid tumor cells that possessed moderate amounts of basophilic cytoplasm with eccentrically placed nuclei. These cells were also showing conspicuos rosette like formations. Histological examination showed a typical endocrine pattern with organoid nests and ribbons of well differentiated monomorphic cells with frequent pseudorosette formation resembling carcinoid tumor of gastrointestinal tract. Neuroendocrine differentiation was confirmed by immunohistochemical positivity for neuron specific enolase, synaptophysin and chromagranin.