Prevalence and Incidence of Cytoplasmic Yellow Bodies in Thyroid Neoplasms

Context.—Cytoplasmic yellow bodies are a common and frequent histologic finding in hyalinizing trabecular adenoma of the thyroid gland, a morphologically distinctive neoplasm, and are visible in fine-needle aspiration biopsy of the tumor. Objective.—To determine the prevalence and frequency of cytoplasmic yellow bodies in common thyroid tumors. Design.—Microscopic slides of random cases of papillary carcinoma (61 cases), follicular adenoma (27 cases), and Hürthle cell adenoma (12 cases) were searched for cytoplasmic yellow bodies. Setting and Patients.—Slides were from patients who had undergone surgery at Mayo Clinic, Rochester, Minn, and were obtained from the Mayo Clinic Tissue Registry. Main Outcome Measure.—Presence or absence of cytoplasmic yellow bodies. Results.—Cytoplasmic yellow bodies were found in papillary carcinoma (62%), follicular carcinoma (22%), and Hürthle cell adenoma (83%) but were very infrequent numerically in each tumor type. Conclusions.—Cytoplasmic yellow bodies may be present in papillary carcinoma and in follicular and Hürthle cell adenomas, but because they are uncommon in these tumors, they are unlikely to be found in fine-needle aspiration biopsy smears. Therefore, cytoplasmic yellow bodies are a useful cytomorphologic indicator of hyalinizing trabecular adenoma of the thyroid gland.