Ectopic Thymic Carcinoma With Tumor Thrombosis: Diagnosing With FDG-PET/CT

A 69-year-old man presented with hoarseness and cervical swelling. CT revealed a neck tumor and lymph node metastasis. Somatostatin receptor scintigraphy (SRS) showed mild lesion uptake. Intravenous tumor thrombus into the right internal jugular and vertebral vein was suggested by FDG-PET/CT and confirmed by Contrast-enhanced CT. Biopsy revealed squamous cell carcinoma (SCC). The tumor location and thrombosis suggested ectopic thymic origin. Immunostaining for markers CD117 and POU2F3 was positive, confirming ectopic thymic SCC. Chemotherapy was initiated, with tumor reduction after 6 months. This case highlights the usefulness of FDG-PET/CT suggestion of tumor thrombus and SRS accumulation in the diagnosis of ectopic thymic carcinoma.