Nuclear crease as a cytodiagnostic feature of papillary thyroid carcinoma in fine-needle aspiration biopsies.

Nuclear crease or grooving was found to be a diagnostic feature of papillary thyroid carcinoma (PTC) in fine-needle aspiration (FNA) biopsies. The FNA biopsies of 37 cases of PTC, 50 cases of multinodular goiter, and 50 cases of follicular neoplasms (45 follicular adenomas and five follicular carcinomas) were examined. The diagnosis was histologically verified in all the cases. The nuclear crease was found to be present in 34 of 37 cases of PTC and in two of five cases of follicular carcinoma. There was no nuclear crease in any of the other cases examined. Thus, it is concluded that the nuclear crease is a fairly constant and characteristic feature of PTC in FNA biopsies and can be used as a valuable diagnostic criterion.