Carcinomatous polyarthritis as a presenting manifestation of papillary carcinoma of thyroid gland

A 61-year-old female presented with 6 months of polyarthralgia associated with constitutional symptoms. These included weight loss, night sweats, lethargy and worsening mobility and activities of daily living. There was no significant medical history. On examination, she had synovitis of multiple joints. Investigations for rheumatoid factor and anti-cyclic citrullinated peptide antibody were negative. There was an acute phase response in the form of raised erythrocyte sedimentation rate and C-reactive protein. Contrast-enhanced computed tomography showed pancreatic and right ovarian cystic lesions, which turned out to be clinically insignificant. Positron emission tomography-computed tomography demonstrated fluorodeoxyglucose avid lesion in the right hemi-thyroid. Ultrasound of thyroid gland showed a 13 mm hyporeflective, irregular, subcapsular nodule in the upper lobe with some microcalcification. Fine needle aspiration cytology was diagnostic of papillary carcinoma, confirmed on total thyroidectomy. Arthritis completely resolved within 8 weeks postoperatively. We report the first case of paraneoplastic carcinomatous polyarthritis in association with a papillary thyroid carcinoma as evidenced by a resolution of joint manifestations and laboratory markers of inflammation posttotal thyroidectomy.