Acquired peripheral pulmonary artery aneurysms: morphological spectrum of disease and multidetector computed tomography angiography findings—cases series and literature review

Background: Acquired peripheral or intraparenchymal pulmonary artery aneurysms (PPAA) are rare entities but are important to recognize because of the associated morbidity. Hemoptysis is their principal complication and is a potentially fatal condition. Purpose: To illustrate the causes, multidetector CT angiography (MDCTA) findings and differential diagnosis of acquired PPAA. Materials and methods: The institutional review boards approved this study. We conducted a retrospective review of the demographic data and the results of clinical and laboratory examinations, and imaging studies of patients managed between January 2012 and January 2017 in two institutions. Results: A total of 19 patients had acquired PPAA that were detected at MDCTA, 9 patients with normal pulmonary artery pressures and 10 with pulmonary hypertension. Nine patients developed PPAA-related acute symptoms. MDCTA features of PPAA include: a lobulated vascular mass, an indistinct irregular arterial wall, aneurysmal thrombosis or wall calcification, findings of impending rupture including perianeurysmal edema, gas or a soft tissue mass. Conclusion: PPAA are rare. In our series, endocarditis and pulmonary hypertension are the PPAA leading causes. The treatment modality preferred is embolization, especially as surgery poses a very high risk for patients with severe pulmonary hypertension. Further clarification of the natural history of these rare arterial aneurysms is needed.