Pulmonary mucormycosis causing pulmonary artery pseudoaneurysm - A rare entity

ABSTRACT

Background: A pseudoaneurysm is an abnormal dilatation or outpouching of the artery which is lined only by the tunica adventitia. Pulmonary artery Pseudoaneurysm is very uncommon and associated with high mortality. Usually congenital but the acquired causes include trauma and infrequently infections mainly bacterial and fungal. Pulmonary mucormycosis is a rare opportunistic fungal infection seen in immunocompromised patients with diabetes, chronic renal failure, malignancies and is one of the most uncommon causes of pseudoaneurysm. Less than 30 cases have been reported worldwide for mucormycosis causing pulmonary artery pseudoaneurysm. Case 1 A 52 year old female who was COVID 19 positive 2 months back, admitted in RICU with recurrent hemoptysis and breathlessness. She is known Diabetic and Hypertensive. As her hemoptysis was persisting she underwent bronchoscopy and a soft mass was noticed in the right lower lobe bronchus which bleeds on touch. Bronchoalveolar lavage sent for microbiology confirmed Mucormycosis. CTPA done post bronchoscopy revealed pseudoaneurysm involving right descending pulmonary artery. Injection Amphotericin B started and surgical resection of right lower lobe done. Case 2 A 65 year old male, diabetic presented with cough and hemoptysis for 20 days with fever. CT thorax was suggestive of necrotising pneumonia in left lower lobe. As his hemoptysis was persisting Bronchoalveolar lavage was taken and the bronchoscopy showed a small swelling in the left lowerlobe bronchus. CECT Thorax was later done which confirmed descending pulmonary artery pseudoaneurysm. Treatment was same as for case 1. Discussion: Fungal pneumonia is a rare acquired cause of pulmonary artery pseudoaneurysm. The pseudoaneurysms are thin walled and easily ruptures producing massive hemoptysis. Infection accounts for 33% of the causes for pseudoaneurysms. Infective causes include pyogenic bacteria like S. pyogenes, S. aureus, Klebsiella and fungus like Mucor, and Aspergillus. Infection leads to chronic inflammation of vessel and leads to weakening of vessel wall which causes the internal layers to rupture. Mucor has the potential to cause direct invasion of the vessel wall leading to pseudoaneurysm. Conclusion: Pulmonary Artery Pseudoaneurysm and Pulmonary mucormycosis are individually uncommon clinical entities, but Pulmonary Artery Pseudoaneurysm due to underlying mucormycosis is a rare condition with a limited description in the literature. A high index of suspicion for both the clinician and radiologist is required and should be suspected in patients with underlying immunosuppression who develop hemoptysis. Pulmonary Artery Pseudoaneurysm can be successfully treated with embolization, but if mucormycosis is confirmed surgical resection is the only option.