title: Diffuse neuroendocrine differentiation in a morphologically composite mammary infiltrating ductal carcinoma: a case report and review of the literature.
abstract: Neuroendocrine differentiation has been reported in both in situ and infiltrating breast cancers. The prognostic significance of neuroendocrine differentiation in mammary carcinoma is unclear. We report a case of infiltrating ductal carcinoma in which there was a morphologically conventional-appearing infiltrating ductal component admixed with nests of cells that resembled a carcinoid tumor and initially mimicked the appearance of intraductal carcinoma. Immunohistochemical stains for synaptophysin and chromogranin demonstrated diffuse, strong positivity uniformly throughout the tumor, even in the more conventional-appearing areas. Electron microscopic examination of tissue retrieved from paraffin blocks was attempted unsuccessfully. We concluded that this was an infiltrating ductal carcinoma with morphologic and immunohistochemical evidence of neuroendocrine differentiation. The case is discussed with a review of the literature and a discussion of nomenclature for tumors of the breast showing variable degrees of neuroendocrine differentiation.
authors.affiliation: Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA. odavid@tulane.edu
authors.forename: Odile
authors.initials: O
authors.lastname: David
authors.forename: Meena
authors.initials: M
authors.lastname: Bhattacharjee
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis*; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis*; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis