Acute Hypoxic Respiratory Failure in Advanced Hepatocellular Carcinoma Secondary to Diffuse Pulmonary Metastases and Malignancy-Associated Hypercoagulability: A Case Report.

We report a 48-year-old male with newly diagnosed moderately differentiated hepatocellular carcinoma (HCC) presenting with diffuse pulmonary metastases with suspected lymphangitic involvement and extensive malignancy-associated thrombosis, including bilateral pulmonary emboli, portal vein thrombosis, and inferior vena cava thrombus. His hospital course was notable for rapid clinical deterioration with progression to acute hypoxic respiratory failure despite supportive management. The primary lesson of this case is that diffuse bilateral pulmonary opacities with concurrent hepatic dysfunction and systemic symptoms should prompt early evaluation for metastatic malignancy and cancer-associated thromboembolism, even when infectious etiologies are initially suspected. The synergistic contribution of lymphangitic carcinomatosis and extensive venous thrombosis to refractory hypoxic respiratory failure, combined with the inability to initiate guideline-directed systemic therapy due to clinical instability precluding variceal screening, underscores the need for early prognostic assessment and timely goals-of-care discussions in advanced HCC.