Hashimoto's Thyroiditis with Squamous Metaplasia.

Hashimoto's thyroiditis is an autoimmune inflammatory disease. Although rare, squamous metaplasia can be seen in Hashimoto's thyroiditis. We present a case of 19 years female who presented with chief complaint of anterior neck swelling for three months. Thyroid Stimulating Hormone (TSH) was 3.93 mIU/L. Ultrasonography neck showed TIRADS (Thyroid Imaging Reporting and Data Systems) 5 lesion. Fine Needle Aspiration Cytology showed Papillary Thyroid Carcinoma. Histopathological examination revealed numerous lymphoid follicles of variable size with clusters of squamous metaplastic cells within the germinal centers of lymphoid follicles and surrounding fibrosis. Some cells showed nuclear clearing. Diagnosis of Hashimoto's thyroiditis with squamous metaplasia was further confirmed by immunohistochemistry. The case presented here is rare and there are very few cases reported in literature so far.