Abstract
A 28-year-old man presented with sudden-onset right lower quadrant abdominal pain and shortness of breath at rest. On examination, he had tachycardia with distant heart sounds and right lower quadrant tenderness. A computed tomography scan showed segmental thickening of the proximal ascending colon and ileum with proximal cecal distension. Echocardiogram confirmed large pericardial effusion with impending tamponade. Video-assisted thoracoscopic surgery was performed for pericardial fluid drainage from a pericardial window. The mediastinal lymph node biopsy revealed metastatic adenocarcinoma cells. A colonoscopy showed a large polypoidal mass in the ascending colon with biopsy confirming poorly differentiated adenocarcinoma, thereby suggesting a possible lymphatic or hematogenous spread without liver or lung involvement.