Fine Needle Aspiration Cytology of Pancreatoblastoma in Adult/Adolescent Patients, One With Histology Mimicking NUT Carcinoma.

Pancreatoblastoma is a rare malignant neoplasm. Cytologic diagnosis is challenging due to the tumor's heterogeneity and requirement of the presence of squamoid nests. Commonly affects children, but the tumor rarely is seen in adult patients. We are reporting three cases from two patients. First patient was a 38-year-old male with a mass in the pancreatic body and numerous hepatic lesions. Fine-needle aspiration (FNA) of the pancreas showed a biphasic malignancy, predominantly composed of a primitive component with intermingled squamoid nests. Subsequent Liver FNA from the same patient showed a similar biphasic malignancy. NUT carcinoma was the top differential and was ruled out by molecular testing. Second patient was a 24-year-old female with a history of pancreatoblastoma related to Gardner's syndrome initially diagnosed in 2015 at age 17, status post distal pancreatectomy and chemotherapy. Celiac lymph node FNA in 2021 showed few cohesive clusters of atypical epithelioid cells, which were highlighted by beta-catenin. Lastly, the literature was reviewed; differential diagnosis and ancillary testing were discussed.