Multimodality Management of Locally Advanced Thymic Squamous Cell Carcinoma Presenting with Superior Vena Cava Obstruction and Dialysis-Dependent Paraneoplastic Renal Failure: A Case Report

Thymic carcinoma is a rare and aggressive epithelial malignancy that frequently presents at an advanced stage with invasion of adjacent mediastinal structures. Superior vena cava (SVC) obstruction is an uncommon but potentially life-threatening manifestation, while paraneoplastic renal failure requiring dialysis is exceptionally rare. We present the case of a 53-year-old female who presented with progressive facial oedema, fatigue, weakness, and nausea secondary to locally advanced thymic squamous cell carcinoma causing SVC obstruction and dialysis-dependent paraneoplastic renal failure secondary to biopsy-confirmed paraneoplastic minimal change disease. Initial PET/CT demonstrated an FDG-avid anterior mediastinal mass measuring 8.3 × 4.2 cm with associated mediastinal and supraclavicular lymphadenopathy. The patient underwent urgent endovascular SVC stenting followed by multimodality treatment with carboplatin and paclitaxel chemotherapy and radical radiotherapy. Serial imaging demonstrated a partial metabolic response; however, residual metabolically active disease persisted within the mediastinum. Following multidisciplinary review, the patient underwent complex salvage surgery including mediastinal tumour resection, bilateral lung wedge resections, vascular graft reconstruction of the innominate vein, partial SVC resection with bovine patch repair, pericardial reconstruction, and bilateral diaphragmatic plication. Histopathological examination demonstrated residual viable squamous cell carcinoma with lymphovascular invasion and nodal metastases, consistent with ypT3N1 disease, with microscopically complete (R0) resection. This case highlights the importance of multidisciplinary management in advanced thymic carcinoma and demonstrates that aggressive multimodality therapy with complex surgical resection may result in successful treatment outcomes in selected patients despite locally advanced disease and severe paraneoplastic complications. At the time of manuscript revision, the patient remains alive without radiological evidence of recurrent disease.