CASTLEMAN DISEASE: A GREAT MIMICKER OF METASTASES IN RADIOIODINE REFRACTORY THYROID CANCER

Abstract

A 27-year-old male underwent total thyroidectomy for thyroid swelling. Histopathology showed papillary thyroid carcinoma [T3 - 6.0 cm] with extra-thyroidal extension. The patient was treated with 150 mCi radioactive iodine (RAI) as adjuvant ablative therapy. Radioiodine refractory disease was identified 1-year post-RAI therapy with elevated thyroglobulin levels and negative I-131 whole body scan. F-18 FDG positron emission tomography/computed tomography scan showed activity in the right thyroid bed and multilevel right cervical nodes. Right-sided modified neck dissection was done, which showed Castleman disease (hyaline vascular type) in right cervical nodes. The most probable cause of elevated tumour markers was found out to be 0.6 cm right thyroid bed nodule on follow-up ultrasonography. Our patient also had coexistent conditions as; osteopoikilosis and Hepatitis C along with thyroid carcinoma. Key words: Castleman disease, lymph node, radioiodine, thyroid cancer