Type A Aortic Intramural Hematoma Without Identifiable Intimal Tear Presenting With Minimal Initial Findings.

Aortic intramural hematoma (IMH) is a subtype of acute aortic syndrome characterized by hemorrhage within the aortic media in the absence of an identifiable intimal tear. Although IMH represents a less frequent presentation of acute aortic syndrome, involvement of the ascending aorta (type A) carries significant morbidity and mortality comparable to classic aortic dissection. Type A IMH has been reported to progress to acute aortic dissection and is associated with an increased risk of aortic rupture due to thinning of the outer aortic media. We report a 77-year-old female with hypertension presenting with acute-onset substernal chest pain and minimal initial findings, including a non-ischemic electrocardiogram and negative serial troponins. Chest radiography demonstrated a widened mediastinum initially attributed to projectional artifacts. Computed tomography angiography (CTA) subsequently revealed a type A intramural hematoma extending from the ascending into the descending thoracic aorta without a visible intimal flap. This case highlights the diagnostic challenge of IMH in hemodynamically stable patients and underscores the importance of maintaining a high index of suspicion and early advanced imaging in suspected acute aortic syndromes.