Unifocal Conventional Papillary Thyroid Carcinoma with Coexisting Caseating Granulomatous Inflammation in India

Thyroid cancer remains one of the leading endocrine malignancies with Conventional Papillary Thyroid Carcinoma (CVPTC) being the most commonly reported cancer. Caseating granulomatous inflammation is an unusual presentation in the thyroid even in places with high incidence of tuberculosis. The association of CVPTC with caseating granulomatous inflammation is infrequent. It can occur as a result of chronic inflammation which subsequently leads to DNA damage by producing nitric oxide and reactive oxygen species resulting in carcinogenesis. Other than tuberculosis, necrotizing granulomas in the thyroid can also be found in association with fungal diseases, plasma cell granulomas and palpation thyroiditis. We report a case of a 46-year-old lady who presented with neck swelling and dysphagia. Examination of the neck showed a firm, non-tender swelling involving the right lobe of the thyroid that moved with deglutination. The thyroid profile was normal. Ultrasound neck revealed a solitary nodule in the right lobe of the thyroid with heterogeneous architecture and increased vascularity. Fine needle aspiration (FNA) suggested Nodular colloid goitre (Bethesda Category II). Intraoperatively, the gland was stony hard and was found adherent to the underlying muscles with no obvious lymphadenopathy. A gross examination of the right hemithyroidectomy specimen revealed a single nodule with the cavity filled with multiple grey-white papillary excrescences along with an adjacent cystic cavity filled with colloid. Histopathological examination was suggestive of unifocal conventional papillary thyroid carcinoma with surrounding caseating granulomatous inflammation involving the right lobe of the thyroid (pT2 Nx Mx). CVPTC with coexisting caseating granulomatous inflammation is a rare presentation. The exact pathology of caseating granulomatous inflammation in our case is unknown. However, chronic inflammation might have played a role in tumorigenesis.