Papillary tissue fragments as a diagnostic pitfall in fine-needle aspirations of thyroid nodules.

Fine-needle aspirates of three thyroid nodules displayed hypercellularity and papillary tissue fragments that suggested neoplasms. Neither microfollicles (either empty or with inspissated colloid) nor the characteristic nuclei of papillary carcinoma were evident. Surgical specimens contained adenomatoid nodules with focal papillary hyperplasia. These cases demonstrate that no single cytologic feature should be used independently in the cytologic diagnosis of thyroid lesions. Tumor cellularity and papillary tissue fragments should not be equated with neoplasia per se; all cytomorphologic features should be evaluated.