Contrast-Enhanced CT Finding of Hot Spot Sign Secondary to Supra Hilar Mass Causing Superior Vena Cava Syndrome: A Case Report.

Superior vena cava syndrome is caused by obstruction of the superior vena cava leading to impaired drainage of the head, neck, and upper chest. A hot spot sign is a rare but sensitive radiological finding and is described as a focal area of hyper-enhancement in Segment IVa (quadrate lobe) of the liver. It demonstrates an area of increased blood flow due to a collateral venous pathway in the setting of superior vena cava obstruction. We report a 60-year-old male presenting with facial and upper limb swelling, dyspnea, cough, weight loss, and prominent anterolateral chest wall veins. Laboratory tests were unremarkable. Contrast-enhanced computed tomography (CT) revealed a right suprahilar mass infiltrating the SVC and azygos vein, with dense opacification of collateral pathways and a hyper-enhancing wedge-shaped area in Segment IVa of the liver, consistent with the "hot spot sign." Bronchoscopy and biopsy confirmed lung adenocarcinoma, positive for TTF-1 and negative for P40. The hepatic hot spot sign arises from portosystemic shunting via the superior vein of Sappey, which connects systemic veins-including phrenic, internal thoracic, and superior epigastric veins-to the left portal vein. Recognition of this pseudo-lesion is critical, as it may mimic metastatic liver lesions and prevent unnecessary invasive procedures such as liver biopsy. Early identification of SVC obstruction facilitates prompt management and prevents complications. Contrast-enhanced CT plays a pivotal role in detecting vascular liver changes secondary to SVC obstruction. Awareness of the hot quadrate sign is essential for early diagnosis and appropriate management of underlying malignancy.