RESUMEN
Background: Malignant pheochromocytomas are rare and aggressive tumors that arise from the adrenal medulla and secrete catecholamines. Patients exhibit episodic symptoms of hypertension, headaches, sweating, and palpitations. The diagnosis is supported by elevated levels of urinary metanephrines, and imaging is used to determine the stage. Treatment involves surgical resection when possible. Case Report: A 57-year-old male presented with hematemesis and melena, and endoscopy revealed upper gastrointestinal bleeding. Imaging showed a malignant pheochromocytoma that had infiltrated the upper lobe of the right kidney and the right lobe of the liver, with a tumor thrombus extending into the hepatic inferior vena cava, the right atrium, and the right ventricle. The patient denied surgery and was treated with palliative medical therapy until he died 3 months later. Conclusion: Although rare, malignant pheochromocytomas may present with upper gastrointestinal bleeding. While metastasis to the liver is a typical manifestation of malignant pheochromocytomas, invasion of the inferior vena cava with infiltration to the right ventricle resulting in tricuspid valve malfunction is a rare finding.