A 13-year-old girl was hospitalized for a second episode of acute upper gastrointestinal hemorrhage. Acute inferior wall myocardial and diffuse subendocardial infarction was diagnosed on the fifth hospital day. Clinical and pathological evaluation established a diagnosis of pseudoxanthoma elasticum (PXE) with characteristic dermatological, ophthalmological, gastrointestinal, and peripheral vascular involvement. Recovery from the myocardial infarction was uneventful despite the development of severe systemic hypertension. Although PXE is a relatively uncommon disease and often seemingly benign, it may be responsible for acute catastrophic events such as gastrointestinal hemorrhage, myocardial infarction, and sudden death in the young.