Cytologic Findings of Cholangioblastic Variant of Intrahepatic Cholangiocarcinoma: A Rare Variant and Cytologic Pitfall

This report describes the cytologic features of cholangioblastic intrahepatic cholangiocarcinoma, a distinct subtype of cholangiocarcinoma from a 32-year-old female with a past medical history remarkable for sclerosing mesenteritis who presented with abdominal pain for several days. Abdominal MRI revealed an 8.5 cm central hepatic mass. Fine needle aspiration (FNA) and concurrent biopsy of the liver mass were performed. The FNA smear showed a monotonous population of singly scattered to loosely cohesive epithelioid to focally plasmacytoid tumor cells with round to oval nuclei, a fine chromatin pattern, and scant to moderate cytoplasm. Prominent nucleoli, mitotic figures, and necrosis were not identified. Focally, an acinar/glandular pattern was identified. Based on cytomorphology, an initial impression of low-grade neuroendocrine tumor was favored. The concurrent biopsy showed tumor cells arranged in trabecular, acinar to solid growth patterns. Immunohistochemical stains performed on the concurrent biopsy showed that the tumor cells were diffuse and strongly positive for CAM 5.2, CK7, albumin ISH, inhibin, and focally positive for synaptophysin and CD56. The tumor cells were negative for chromogranin, arginase, glypican-3, CD34, INSM1, GATA3, PAX-8, SF-1, SALL4, HepPar1, and CDX2. The overall findings were consistent with intrahepatic cholangiocarcinoma, cholangioblastic variant. To our knowledge, this case represents the first report of the cytologic features of a cholangioblastic variant of intrahepatic cholangiocarcinoma on FNA.