Focal Hepatic Hot Spot Sign Mimicking Active Extravasation on CT Angiography in Superior Vena Cava Syndrome: A Case Report

Introduction

Caused by portosystemic venous shunting, the focal hepatic hot spot sign (or hot quadrate sign) is a radiologic finding most commonly associated with superior vena cava (SVC) obstruction. On contrast-enhanced imaging, this finding may mimic active hepatic extravasation or focal hepatic pathology, posing a diagnostic challenge in the emergency department (ED). Case Report: We report a case of a 70-year-old man with progressive cognitive decline and hypoxemic respiratory failure requiring intubation. Computed tomography (CT) angiography of the chest demonstrated a focal area of intense contrast enhancement in the left hepatic lobe, initially concerning for active extravasation. Further review of the imaging revealed a right upper lobe lung mass and a large mediastinal mass causing high-grade SVC stenosis. The hepatic finding was subsequently identified by the reading radiologist as a focal hepatic hot spot sign representing a vascular pseudolesion due to collateral venous flow. The patient was diagnosed with SVC syndrome secondary to malignancy and underwent chemotherapy before transitioning to comfort care.