226 Heterotopic Pancreatic Tissue in a Thyroid Nodule

Introduction/Objective Heterotopia is the presence of mature tissue outside its normal location, without connection to the organ it normally exists in. Pancreatic heterotopia in the thyroid has only been previously documented once. In that case, the pancreatic tissue was associated with a presumed foregut remnant. There have been no prior documented cases of pure heterotopic pancreatic tissue in a thyroid nodule. Methods/Case Report A 73-year-old female underwent parathyroidectomy for hyperparathyroidism. Upon resection, a calcified nodule in the left thyroid gland was found to have a cyst lined by columnar epithelium and a collection of acinar-appearing cells with basophilic basally oriented nuclei and eosinophilic apical zymogen granules within the cyst wall. Insulinoma-associated protein 1 (INSM1) immunostaining was focally positive in this region. Additionally, trypsin showed granular cytoplasmic positivity in the acinar cells. Finally, CK19 was strongly positive in the columnar epithelium, confirming pancreatobiliary origin. Results NA Conclusion While there are several reported cases of heterotopic thyroid in the pancreas, there is no literature on heterotopic pancreas in the thyroid. Longitudinal follow-up with the current patient will be beneficial to identify any new nodules or symptoms, which may provide further insight into the pathogenesis and presentation of heterotopic pancreatic tissue in the thyroid gland.