An Unusual Case of Superior Vena Cava Syndrome Caused by the Intravascular Invasion of an Invasive Thymoma
A 39-year-old female visited the emergency department suffering from facial edema and dyspnea for 1 week. She was previously healthy and had never received any intravascular procedure in the heart or great veins. An initial neck computed tomography (CT) revealed extensive thrombosis in the LBCV and SVC extending into the right atrium. To define the cause of thrombogenic states, laboratory tests including antinuclear antibody, anticardiolipin antibody, lupus coagulant, protein C and protein S activities, antithrombin III, factor V Leiden mutation, human leukocyte antigen-B51 and skin pathergy test were performed, but all results were normal. Despite anticoagulation treatment with 60 mg of enoxaparin twice a day for 10 days, the extent of SVC thrombosis was not reduced.\nTo investigate her underlying pathologic condition, a chest CT was additionally performed, and the anterior mediastinal mass invading the LBCV and SVC was defined (). An additional positron emission tomography (PET)-CT performed to evaluate the extent of the mass and the degree of malignancy showed a well-defined hypermetabolic lesion with the maximum standardized uptake value (SUVmax) 6.0 along the LBCV extending into the proximal SVC ().\nBased on these results, she was presumed to have a malignant mediastinal tumor such as invasive thymoma or thymic carcinoma invading the adjacent great veins, and en bloc resection of the tumor with the involved vessels was performed. Pathologic findings confirmed her diagnosis as a SVC thrombus with type B2 thymoma, a predominantly lymphocytic thymoma with scattered plump cells and vesicular nuclei, invading the LBCV and SVC (), and the postoperative stage was defined as III based on Masaoka's classification.\nThe patient was discharged from the hospital 16 days after the operation, and has been on the course of postoperative radiation and chemotherapy as adjuvant treatment.