Papillary Thyroid Microcarcinomas: Does Sub-typing Predict Aggressive Clinical Behavior?

The most common malignant neoplasm affecting the thyroid gland is papillary thyroid carcinoma (PTC). PTC can demonstrate a number of morphologic variants including but not limited to classic, follicular, and tall cell. Each of these morphologic sub-types carry distinct clinical characteristics such that certain variants, like tall cell, behave more aggressively than others. Papillary thyroid carcinomas measuring less than or equal to 1.0 cm are classified as microcarcinomas. Though these lesions are thought to be clinically indolent, we hypothesized that, like their larger counterparts, certain histologic variants may lead to worse patient outcomes. To test our hypothesis, we analyzed our pathology archives between the years of 2009-2020 for papillary thyroid microcarcinomas and assessed whether different morphologic features correlated with more aggressive clinical behavior. Our findings suggest that certain variants exhibit features that portend a more worrisome clinical course and thus papillary thyroid microcarcinomas should be sub-typed to help predict patient outcome.