concurrent papillary thyroid carcinoma and synovial carcinoma of the neck in an adult male

Introduction: synovial sarcoma makes up 8–10% of all soft tissue sarcomas, and constitutes 3–10% of all sarcomas occurring in the head and neck region. it shows male predominance (3:2), and the mean age of presentation is 30 years. case report: a 51-year-old gentleman presented with right-sided neck swelling which had been progressively increasing in size for the past 2 years. a computed tomography (ct) scan revealed a large heterogeneously enhancing mass on the right side of the neck measuring 7.5 × 6.2 cm. biopsy of an enlarged node revealed papillary thyroid carcinoma. the patient subsequently underwent total thyroidectomy with right neck dissection. final histopathology revealed a papillary carcinoma of the thyroid, and the right-sided mass was shown to be monophasic synovial sarcoma. conclusion: we present a case of a concurrent pathology of neck papillary thyroid carcinoma with monophasic synovial sarcoma. we experienced difficulty in diagnosis and misdirection due to raised c-reactive protein (crp) levels, until final histopathology of the neck mass.