Fine-needle aspiration of a pancreatic neuroendocrine tumor with prominent rhabdoid features.

Pancreatic neuroendocrine tumors (PanNETs) are uncommon neoplasms that conventionally possess architectural and cytomorphological features seen in neuroendocrine neoplasms found at other sites. When present, these features often allow rapid identification of neuroendocrine differentiation and an accurate diagnosis. Here, we report the cytologic findings seen on fine-needle aspiration (FNA) of a PanNET with distinct rhabdoid features. This morphology is rare in PanNETs and has been reported in only two case series examining surgical resection specimens and has not been described on FNA. It is important to recognize this morphology as this variant appears to portend an aggressive clinical course. Furthermore, unfamiliarity with this morphologic variant may lead to a larger initial differential and thus delay final diagnosis.