Hashimoto's Thyroiditis Mimicking Papillary Thyroid Carcinoma – False Positive Cytology With Histopathological Correlation- A Rare Case Report

Abstract

Background:- It is very rare that cytological diagnosis of papillary thyroid carcinoma by FNAC could not be conrmed by histological evaluation. One of the reasons for positive cytological nding and negative histological nding of papillary thyroid carcinoma is false positive diagnosis. Hashimoto's thyroiditis an autoimmune disease can be so extensive may mimic as papillary thyroid carcinoma because it may cause massive destruction of thyroid gland and may show similar nuclear features like Ptc. A Case Report:- 35-year old female, with a midline neck swelling of size (4x3)cm2 for one year. On FNAC the thyroid swelling was diagnosed as suspicious for papillary thyroid carcinoma. (Bethesda category v). However post operative diagnosis was conrmed as Hashimoto's thyroiditis. Hi Conclusion:- stomorphology in conjunction with biochemical ndings are necessary to conrm diagnosis of Hashimoto's Thyroiditis. False positive FNAC result is a pitfall of FNAC. Awareness of cytopathologist about pitfall of FNACS and strict adherence to adequacy criteria can reduce false positive rates.