Xanthogranulomatous Reaction Mimicking Recurrence of Papillary Thyroid Carcinoma after Lobectomy: A Case Report

Xanthogranuloma is an uncommon and chronic inflammatory reaction characterized by the accumulation of foamy macrophages in various body tissues such as the skin, gallbladder, and kidney, and is often mistaken for malignancy. The aim of this report is to introduce a case of severe xanthogranulomatous reaction in the thyroid bed following previous lobectomy treatment of papillary thyroid carcinoma, which has now been re-operated with a clinical diagnosis of tumor recurrence.
Case Report: The patient is a 42-year-old woman who underwent subtotal thyroidectomy (lobectomy) two years ago due to a neck mass and was diagnosed with papillary thyroid carcinoma. Now, the patient referred with a sore throat. During the examination, the mass was felt at the previous thyroidectomy site, which was re-operated after ultrasound and CT scan with the diagnosis of recurrence of the previous tumor. In the evaluation of the pathology of the thyroid tissue along with the surrounding adhesive tissues, and in the initial sections of the cell plates, abundant clear and granular cytoplasm between the muscles and CD connective tissue as well as extensive infiltration of fat were observed. After the examination and performing immunohistochemistry for CD68, S100 and CK markers, all negative cases, except the marker CD68, which is specific for macrophages, were positive, suggesting the diagnosis of xanthogranuloma. Then, all tissues were checked for recurrence of papillary carcinoma, and the result was negative.

Based on the results of this reported case, xanthogranuloma should be considered in patients undergoing thyroid lobectomy with recurrence of papillary thyroid carcinoma.