Incidental and rare findings in thyroidectomy specimens

Background: We have reported three cases of incidental findings of solid cell nests, ectopic thymus with parathyroid tissue and thyrolipoma in thyroidectomy specimens. These patients presented clinically as nodular thyromegaly and were directed for FNAC. Ultrasound findings were suggestive of nodular goiter and on histopathology revealed features compatible with nodular goiter along with incidental findings of solid cell nests, ectopic thymus with parathyroid tissue and thyrolipoma. Differential diagnosis of thyroid nodules should include these rare diagnostic findings which create confusion in thyroid pathology as they mimic malignancies both clinically and histologically and also because neoplasms may arise in the background of these rare findings. Objectives: To analyze clinicopathological findings in thyroid specimens, to correlate with Ultrasonography (USG), Fine needle aspiration cytology (FNAC), hormonal assay and immunohistochemistry. Materials and methods: All the specimens were analyzed and routinely processed for histopathology and stained with haematoxylin and eosin. Results: Incidental associated findings were noted in three cases composed of solid cell nests, ectopic thymus with parathyroid tissue and thyrolipoma. Conclusion: Three incidental and relatively unusual findings of solid cell nests, ectopic thymus with parathyroid tissue and thyrolipoma were diagnosed on histopathology. These lesions of thyroid gland must be differentiated from close mimickers including both non-neoplastic and neoplastic lesions clinically, radiologically and microscopically. Though benign and rare, these incidental findings should be thought of in all the thyroid specimens to avoid confusion with neoplastic thyroid pathology and also because they carry a potential risk for developing into neoplastic lesions.