When a teenage boy presented to ED with a three-day history of sharp chest pain, suggestive of perimyocarditis, doctors found the cause hard to pin down.

The 17-year-old denied any prodromal symptoms or trauma, reporting fatigue and dyspnoea on exertion.

An ECG showed diffuse ST-segment elevation, while tests were notable for elevated troponin I — both concerning for the acute inflammatory condition.

Doctors ordered a chest X-ray, which revealed a linear density in the anterior mid-chest.