Introduction: Pulmonary artery aneurysm (PAA) is a rare condition and associated with multiple pathologies. In most cases there are reports of dyspnea and palpitation, however, some patients are completely asymptomatic. Its natural history is uncertain and there are no clear guidelines about its treatment and monitoring.Method: This is one case report, obtained through data from medical records of a reference hospital, located in the city of Juazeiro do Norte, Ceará, Brazil.Case Report: Patient, female, 64 years old, healthy, sought medical assistance after a clinical picture of drug allergy. The physical examination performed at admission revealed hyperdynamic precordium associated with systolic thrills and murmur. Her chest radiography (X-ray) revealed a mediastinal widening, which after CT evaluation, it was found that it was a large aneurysm of trunk of the pulmonary artery. As it remained asymptomatic throughout the investigation and she refused to undergo surgical treatment, there was the adoption of a conservative conduct only with an outpatient treatment.