Chronic and Atypical Presentation of Superior Vena Cava Syndrome: A Case Report.

We report the case of a 66-year-old woman with an unusually chronic presentation of superior vena cava syndrome (SVCS), characterized by more than two decades of collateral venous development before definitive evaluation. The patient presented with a 10-month history of persistent dry cough and long-standing venous engorgement of the supraclavicular, thoracic, and abdominal regions, which she recalled dating back to the mid-1990s. Despite the extent of venous changes, she denied constitutional symptoms, respiratory distress, or neurological compromise. Physical examination confirmed prominent collateral circulation, tracheal deviation, and absent breath sounds in the right apex. Laboratory investigations were within normal limits except for mild anemia and dyslipidemia. Computed tomography of the chest revealed a large bilobulated mediastinal mass, measuring 70 × 67 × 121 mm, compressing the superior vena cava and the brachiocephalic trunk, with associated venous dilatation. Differential diagnosis included thymoma, lymphoma, and germ cell tumor. Ultrasound-guided biopsy demonstrated malignant epithelial cells with tubulo-glandular architecture, consistent with adenocarcinoma. Unlike most malignant SVCS cases, which present acutely and demand urgent management, this patient remained clinically compensated for decades, highlighting the remarkable capacity of venous adaptation. The protracted course allowed a complete diagnostic workup and histopathological confirmation before therapeutic decisions were required. This report underscores the importance of recognizing collateral venous networks as a clinical sign of central venous obstruction, even in the absence of acute symptoms. It also illustrates the relevance of physical examination in guiding diagnosis in an era dominated by imaging. Awareness of such atypical and indolent cases can help clinicians avoid delayed recognition and ensure timely oncologic management.