SILENT CHEST, LOUD SHOULDER: ACUTE MYOPERICARDITIS PRESENTING AS ISOLATED RIGHT SCAPULAR PAIN

Acute myocarditis has a highly variable presentation; its infarct-like phenotype, with chest pain, ST-segment changes, and troponin elevation, is well recognized, but atypical, non-chest-pain presentations are rarely described. We report a 41-year-old man admitted for isolated, intense right scapular pain radiating to the right arm, occurring in a febrile context two weeks after a flu-like illness, without chest pain at any stage. Electrocardiography showed lateral ST-segment elevation with reciprocal inferior changes, and high-sensitivity troponin I was markedly elevated (27,016 ng/L) alongside severe inflammation (CRP 195.5 mg/L). Echocardiography showed regional hypokinesia with preserved ejection fraction. Coronary angiography was normal, and pulmonary embolism and intra-abdominal pathology were excluded. Cardiac magnetic resonance demonstrated findings compatible with acute diffuse myocarditis and a small pericardial effusion, establishing acute myopericarditis as the final diagnosis. The patient improved with aspirin and colchicine. This case illustrates that isolated scapular pain, plausibly referred via the phrenic nerve, can be the sole presenting feature of myopericarditis mimicking an ST-elevation myocardial infarction, and underscores the role of cardiac MRI in diagnostic reclassification when coronary angiography is unremarkable.