Suspicious Segmental Pulmonary Artery Aneurysm With Nontuberculous Mycobacterial Infection: A Report of a Rare Case

Nontuberculous mycobacteria (NTM) are well-established pulmonary pathogens across all demographics; conversely, pulmonary artery aneurysms (PAAs) represent rare and potentially life-threatening vascular complications. The pathophysiological association between chronic NTM infection and the development of PAAs remains largely underexplored. A 69-year-old man with a history of untreated NTM infection presented to our facility with a chief complaint of hemoptysis. Initial diagnostic imaging suggested the presence of a PAA in a branch of the pulmonary artery. Consequently, a multidisciplinary consultation ensued to determine the true structural classification of the lesion, weighing a PAA against an acquired, infection-mediated pseudoaneurysm. Subsequent bronchoscopy and culture analysis of the bronchial lavage fluid grew Mycobacterium abscessus complex. The patient was managed with intravenous antibiotics and supportive respiratory therapies. Following multidisciplinary consultations, the cardiology service concluded that the PAA was an incidental finding likely secondary to an infectious etiology. The patient was deemed a nonsurgical candidate and was discharged with plans for close outpatient follow-up with cardiology, pulmonology, and infectious disease specialties. This case details a rare clinical intersection: an incidental PAA discovered during the workup of an active, untreated M. abscessus complex infection. While the patient was managed conservatively without surgical intervention, the concurrence of these pathologies underscores a critical diagnostic consideration. Due to the scarcity of documented literature on NTM-associated vascular complications, this presentation highlights the importance of recognizing chronic atypical mycobacterial infections as potential drivers of adjacent vascular wall degradation. Further research is warranted to elucidate the mechanisms by which NTM-mediated inflammation induces vascular wall injury, potentially predisposing patients to aneurysm formation.