Case of Carcinoma Breast with Unusually Large Tumor Thrombus in Superior Vena Cava Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography Computed Tomography Scan.

A 60-year-old female with triple negative breast cancer, postsurgery, neoadjuvant chemotherapy and radiotherapy, on follow-up had facial puffiness and giddiness. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) done for suspected recurrence evaluation revealed a large tumor thrombus (TT) in superior vena cava (SVC) with radiological evidence of SVC obstruction. 18F-FDG PET/CT also showed evidence of FDG avid brain metastases, lymph nodal metastases, and metastatic soft tissue deposits. This case of unusually large TT in SVC detected on 18F-FDG PET/CT highlights the ability of 18F-FDG PET/CT to identify TT and clearly demonstrate the pattern of disease in suspected recurrence in triple negative breast cancer patients.