Pancreatic Metastasis from Papillary Thyroid Carcinoma Diagnosed by Endoscopic Ultrasound-Guided Fine Needle Aspiration A Case Report

Background The incidence of papillary thyroid carcinoma that has metastasized to the pancreas is extremely rare. To date, only 2 cases have been reported in the literature. Case A case of pancreatic metastatic papillary thyroid carcinoma occurred in an 82-year-old man with a prior history of thyroid papillary carcinoma, resected 5 years earlier. Due to recurrent pancreatitis, endoscopic ultrasound (EUS) was performed and showed a pancreatic neck mass as well as diffuse changes of chronic pancreatitis. Fine needle aspiration was performed under EUS. The microscopic examination showed a highly cellular smear composed of conspicuous papillary architecture at low magnification. In addition to papillae, tumor cells were arranged in syncytial aggregates and scattered singly in the background. The tumor cell population was monotonous, with high nuclear/cytoplasmic ratios, fine powdery chromatin and small nucleoli. Nuclear changes characteristic of papillary thyroid carcinoma were identified. Nuclear folds and grooves were prominent. Occasional cells showed intranuclear cytoplasmic inclusions. The tumor cells in the cell block were positive for thyroglobulin. Conclusion EUS-guided fine needle aspiration cytology can be a reliable method for the diagnosis of metastatic papillary thyroid carcinoma of the pancreas. The cytomorphology in combination with the clinical history and immunohistochemical findings can indicate a definitive diagnosis and avoid additional time-consuming diagnostic procedures for appropriate clinical management. (Acta Cytol 2010;54:640-644)