Neuroendocrine ductal carcinoma in situ (NE-DCIS) of the breast: cytological features: Report of 5 cases of aspiration cytology

Abstract

The cytopathological features of neuroendocrine ductal carcinoma in situ (NE-DCIS) of the breast were evaluated. We reviewed the cases of 5 patients with cytological materials diagnosed as having NE-DCIS (age 50–80, mean 70.6 years old). The characteristic cytological findings were as follows: clear bleeding in the background, mucinous materials and vessel components, abundant cell components, cell clusters that show loose intercellular adhesion, no myoepithelial components, oval- to polygonal-shaped cells with a granular cytoplasm stained light green, uneven distribution of round- to oval-shaped nuclei, dense nuclear chromatin with a fine or minute granular pattern, and one or a few small nucleoli. The tumor size was less than 10 mm in 4 patients and 25 mm in one patient. Histopathologically, the tumor was located in dilated ducts and showed solid or tubular patterns with abundant vessels and mucinous components in the stroma. Immunohistochemically, the tumor cells were positive for synaptophysin (4/5), chromogranin A (4/5), and CD56 (3/5). The average Ki-67 index of 4 patients was 8.5% (0–19.1). As the differential diagnosis for these patients was intraductal papilloma (IDP), the characteristic cytological findings mentioned above were useful for distinguishing between NE-DCIS and IDP.