FOLLICULAR ADENOMA THYROID WITH CLEAR CELL CHANGES- A RARE CASE REPORT.

Follicular lesions in thyroid nodule are common findings while investigating them by fine-needle aspiration cytology (FNAC). Histologically, these lesions may represent a cellular nodule in a goiter, a follicular adenoma, or a carcinoma. Cellular changes that occur in clear cytoplasm in thyroid lesions are caused by glycogenation, intracellular accumulation of thyroglobulin, dialatation and hypertrophy of mitochondrial cells and golgi complex hypertrophy which is due to excessive secretion of Thyroid stimulating hormone(TSH). A 28 year female, housewife, presented with a gradually increasing swelling in midline of neck since 2 years. On examination, swelling was present on anterior border of sternocledomastoid, 3x2cm in size, oval and with diffuse margins. It was non-tender, moved on deglutition, non-reducible and transillumination negative. The patient had normal thyroid functions with free T4 and TSH within normal range. No capsular or vascular invasion was seen. A diagnosis of Clear cell Follicular adenoma thyroid was made. Pure Follicular adenomas are the common lesions of thyroid and arise from follicular epithelium. They are usually single and well-encapsulated lesions. These lesions are more common in females and are mostly benign. Any thyroid lesion with clear cell features warrants further histopathological assessment as clear cell changes are not appreciated in cytological smears. Our case presents the pathology of pure clear cell Follicular adenoma which is rarely seen.