Cytologic and architectural mimics of papillary thyroid carcinoma. Diagnostic challenges in fine-needle aspiration and surgical pathology specimens.

In this paper, we review those pathologic entities that may mimic papillary thyroid carcinoma. These include specimen preparation and handling issues such as decalcification, frozen section, and artifacts occurring following fine-needle aspiration (FNA). Also discussed are true disease entities, including chronic lymphocytic thyroidits, benign papillary hyperplastic lesions, hyalinizing trabecular neoplasm, and post-FNA changes. Both the cytologic and histopathologic preparations containing these changes are reviewed and illustrated; guidelines for distinctions among these entities are provided.