Exostotic Compression of the Heart Mimicking Angina: A Rare Thoracic Osteochondroma.

Primary tumors of the bony chest wall are rare. A young ultramarathon runner presented with angina-like chest pain with normal findings on cardiac workup. Cross-sectional imaging revealed a 4.2-cm lesion abutting the pericardium concerning for an osteochondroma. This case illustrates how exostotic compression from a rib lesion can mimic angina and prompt extensive cardiac evaluation while the true cause remains unrecognized, highlighting the need for timely cross-sectional imaging and early surgical intervention. Video-assisted thoracoscopic surgery confirmed a 4.2-cm mass impinging on the pericardium, and resection with reconstruction provided complete symptom resolution and a return to running.