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A Mycotic Pulmonary Artery Aneurysm Presenting as an Endobronchial Mass* FREE TO VIEW

Mark T. Dransfield; James E. Johnson
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*From the University of Alabama at Birmingham, Birmingham, AL.

Correspondence to: James E. Johnson, MD, FCCP, Division of Pulmonary, Allergy, and Critical Care, BDB 390, 1808 Seventh Ave South, Birmingham, AL 35294-0012; e-mail: jjohnson@pulm. dom.uab.edu



Chest. 2003;124(4):1610-1612. doi:10.1378/chest.124.4.1610
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We report the case of a 49-year-old woman who developed an endobronchial mycotic pulmonary artery aneurysm (PAA) as a complication of pneumonia. After presenting with patchy infiltrates, she developed right lung atelectasis. A noncontrast chest CT scan revealed a mass in the right hilum, and bronchoscopy identified an obstructing lesion in the right mainstem bronchus. Unfortunately, biopsy caused massive hemorrhage, and the patient died. An autopsy identified a mycotic PAA that had invaded the right mainstem. The case suggests that a contrasted CT scan should be included in the evaluation of endobronchial masses and that PAA should be included in the differential diagnosis of such lesions.

Figures in this Article

Pulmonary artery aneurysms (PAAs) occur rarely and are even less frequently clinically evident. They can be congenital or acquired in origin. Prior to the widespread availability of antibiotics, acquired PAAs were most often the result of tuberculosis or syphilis. More recently, other organisms have been identified as important causes of acquired PAAs.1 In the is article, we report the case of a patient with a mycotic PAA due to pneumonia that presented as an endobronchial mass. Unfortunately, this was not recognized, and the patient died as a result of an endobronchial biopsy.

The patient was a 49-year-old white women without a significant medical history who presented with a 5-day history of productive cough and chest pain. Her symptoms progressed despite therapy with prednisone and azithromycin. A chest radiograph revealed a right lower infiltrate, and the patient was admitted to the hospital. IV levofloxacin therapy was administered, and vancomycin and tobramycin were added to the regimen after 6 days. Eight days after hospital admission, a chest radiograph revealed total atelectasis of the right lung. On the ninth hospital day, a noncontrasted chest CT scan revealed alveolar infiltrates throughout the right lung with multiple areas of cavitation. In addition, a right hilar mass 4 × 4 cm in size was identified (Fig 1 ). On day 10, she underwent bronchoscopy, and a mass was seen arising from the anterior aspect of the right mainstem bronchus. No biopsy specimens were obtained, but later that day the patient underwent a right thoracotomy with wedge resection of an area of cavitation as well as repeat bronchoscopy with endobronchial biopsy. Both procedures were complicated by hemorrhage, although the hemorrhage was eventually controlled. The open-lung biopsy revealed bronchopneumonia with cultures growing Streptococcus viridans. Endobronchial biopsy specimens revealed nonspecific inflammation. Therapy with antibiotics were continued for 10 more days, and the patient was transferred to our facility.

On hospital admission, the patient was afebrile with a heart rate of 113 beats/min and a BP of 107/66. Oxygen saturation was 97% on 6 L by nasal cannula. Her physical examination revealed decreased breath sounds over the right hemithorax but was otherwise normal. The initial results of laboratory work revealed a WBC count of 13,900 cells/μL with 90% neutrophils but was otherwise unremarkable, with normal hematocrit, platelet count, prothrombin and partial thromboplastin times, and serum chemistry levels. An HIV test obtained at the referring hospital was negative. A chest radiograph confirmed total opacification of the right hemithorax.

The day following transfer, the patient was taken to the operating room for rigid bronchoscopy. Again, a mass was identified in the right mainstem bronchus. Unfortunately, massive bleeding was noted after the first biopsy and, despite left mainstem intubation and fluid resuscitation, the patient became pulseless. She could not be revived despite aggressive transfusion and continued resuscitative efforts.

An autopsy confirmed the presence of extensive necrotizing pneumonia. Also noted was a mycotic aneurysm of the right pulmonary artery that extended into the wall of the right mainstem bronchus (Fig 2, 3 ).

It is difficult to establish an accurate estimate of the incidence of PAA as prior studies have used inconsistent definitions, have focused on a particular etiologic subtype, and were reported before the introduction of modern antibiotics. Despite these limitations, it is clear that the problem is very rare, as evidenced by the 1947 study of Deterling and Clagett2 of proximal PAA in which only eight cases were documented in > 109,000 autopsies. PAA can occur with or without arteriovenous connection and can be congenital or acquired in origin. Although acquired PAA can be idiopathic, such as that seen in Behçet syndrome, or the result of structural cardiac abnormalities or thoracic trauma, infection is the most important cause.1

In addition to Mycobacterium tuberculosis and Treponema pallidum, other organisms such as Staphylococcus aureus, streptococcal species, Corynebacterium diptheriae, Candida species, and Aspergillus species have been implicated as causes of mycotic PAA.1 Mycotic PAAs usually form as a result of bloodstream infection and endovascular seeding. This mechanism is supported by the fact that mycotic PAA have occurred in conjunction with IV drug abuse and endocarditis in which endovascular seeding is the only source of vessel infection. In cases of pneumonia, some authors have documented angiocentric infiltrates without evidence for airway inflammation, suggesting that endovascular seeding is again the primary event. In cases in which an aneurysm develops within the pneumonic lung, it is impossible to rule out a pathogenesis similar to that associated with Rasmussen aneurysm in which mycobacteria invade the outer vessel wall and spread medially, leaving it vulnerable to rupture. In our case, the patient had no history of syphilis or tuberculosis and, although there was no history of IV drug abuse or evidence for endocarditis, the PAA was not within an area of pneumonia, suggesting that it stemmed from vascular seeding.

PAAs are usually apparent on the chest radiograph, although they may not be identified as such. Congenitally acquired PAAs associated with arteriovenous shunts may appear as subpleural nodules. Proximal PAAs are also usually visible but can be confused with hilar nodes, aortic dilatation, and primary lung tumors.1,3 In our case, the chest radiograph showed no evidence of abnormalities of the pulmonary artery. In addition, the progression of patchy infiltrates to right lung atelectasis was highly suggestive of endobronchial disease, which is frequently due to neoplasia. This possibility was appropriately evaluated with a chest CT scan, however, the scan was obtained without contrast, which may have provided clues that the mass was vascular in origin. A careful review of the image at the level of the right pulmonary artery shows no tissue plane between it and the right mainstem bronchus. Unfortunately, the possibility of an endobronchial PAA was not considered, and the patient experienced a fatal hemorrhage at the time of the biopsy.

Major hemorrhage is an unusual complication of bronchoscopic biopsy,4 although massive bleeding from unusual sources such as aberrant bronchial arteries has been described.5 Fatal hemorrhage from mycotic PAAs also has been reported previously,6 however, to our knowledge there have been only two previously reported cases of bronchoscopically identified endobronchial PAAs. Gibbs and Hami7 described a 25-year-old man with a smooth, orange-red lesion that occluded the takeoff of the posterior segment of the right lower lobe. A PAA was not suspected, and attempts at biopsy resulted in a fatal hemorrhage. Autopsy revealed that the mass was in direct communication with the pulmonary artery. St. Christov and Kanasirski8 described a patient with a 2.5-cm mass filling the left mainstem bronchus. The lesion bled spontaneously during bronchoscopy, and the patient died. A postmortem examination revealed an aneurysm encasing the bronchus with medial necrosis in the vessel wall.

The management of PAAs involving the main pulmonary trunk is limited to surgical aneurysmectomy. In cases involving the left or right main pulmonary arteries, pneumonectomy is also an option. Smaller resections and embolotherapy may be useful for more distal lesions.1,9

This case highlights how the diagnosis of mycotic PAA can be overlooked. Total lung atelectasis, as was seen in our patient, is routinely considered to be highly suggestive of endobronchial neoplasia. Based on the available data, there were few clues to suggest that the lesion could represent an aneurysm. A contrasted CT scan may have identified the vascular nature of the lesion and should be considered in the evaluation of possible endobronchial tumors. Also, although rare, PAAs should be included in the differential diagnosis of endobronchial masses.

Abbreviation: PAA = pulmonary artery aneurysm

Figure Jump LinkFigure 1. Noncontrast chest CT scan at the level of the right pulmonary artery showing a 4 × 4-cm mass in the right hilum. The lesion proved to be a mycotic PAA.Grahic Jump Location
Figure Jump LinkFigure 2. Autopsy specimen of the right lung. Left: white arrow = trachea; black arrow = right mainstem bronchus. Right: black arrow = right pulmonary artery. The probe is shown entering the ruptured wall of the PAA within the right mainstem bronchus and exiting into the right pulmonary artery.Grahic Jump Location
Figure Jump LinkFigure 3. Microscopic section of the PAA showing obliteration of the wall of the right pulmonary artery by acute inflammation (white arrow) and its fusion to the wall of the right mainstem bronchus (black arrow) [hematoxylin-eosin, original ×40].Grahic Jump Location
Bartter, T, Irwin, RS, Nash, G (1988) Aneurysms of the pulmonary arteries.Chest94,1065-1075. [CrossRef] [PubMed]
 
Deterling, RA, Clagett, DT Aneurysms of the pulmonary artery: review of the literature and report of a case.Am Heart J1947;34,471-498. [CrossRef] [PubMed]
 
Chung, CW, Doherty, JU, Kotler, R, et al Pulmonary artery aneurysm presenting as a lung mass.Chest1995;108,1164-1166. [CrossRef] [PubMed]
 
Cordasco, EM, Mehta, AC, Ahmad, M Bronchoscopically induced bleeding: a summary of nine years’ Cleveland Clinic experience and review of the literature.Chest1991;100,1141-1147. [CrossRef] [PubMed]
 
Maxeiner, M Lethal hemoptysis caused by biopsy injury of an abnormal bronchial artery.Chest2001;119,1612-1616. [CrossRef] [PubMed]
 
Morgan, JM Fatal haemorrhage from mycotic aneurysms of the pulmonary artery.Thorax1986;41,70-71. [CrossRef] [PubMed]
 
Gibbs, PM, Hami, A Pulmonary arterial aneurysm presenting as an endobronchial mass.Thorax1995;50,1013-1014. [CrossRef] [PubMed]
 
St Christov, V, Kanasirski, P Aneurysma des linken haupastes der arteria pulmonaris mit ruptur in den linken hauptbronchus.Zentralbl Allg Pathol1966;109,524-526. [PubMed]
 
Bowler, RP, Durham, J, Schwarz, MI Massive hemoptysis from a pulmonary artery aneurysm associated with an emphysematous bulla.Chest1998;113,1130-1131. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1. Noncontrast chest CT scan at the level of the right pulmonary artery showing a 4 × 4-cm mass in the right hilum. The lesion proved to be a mycotic PAA.Grahic Jump Location
Figure Jump LinkFigure 2. Autopsy specimen of the right lung. Left: white arrow = trachea; black arrow = right mainstem bronchus. Right: black arrow = right pulmonary artery. The probe is shown entering the ruptured wall of the PAA within the right mainstem bronchus and exiting into the right pulmonary artery.Grahic Jump Location
Figure Jump LinkFigure 3. Microscopic section of the PAA showing obliteration of the wall of the right pulmonary artery by acute inflammation (white arrow) and its fusion to the wall of the right mainstem bronchus (black arrow) [hematoxylin-eosin, original ×40].Grahic Jump Location

Tables

References

Bartter, T, Irwin, RS, Nash, G (1988) Aneurysms of the pulmonary arteries.Chest94,1065-1075. [CrossRef] [PubMed]
 
Deterling, RA, Clagett, DT Aneurysms of the pulmonary artery: review of the literature and report of a case.Am Heart J1947;34,471-498. [CrossRef] [PubMed]
 
Chung, CW, Doherty, JU, Kotler, R, et al Pulmonary artery aneurysm presenting as a lung mass.Chest1995;108,1164-1166. [CrossRef] [PubMed]
 
Cordasco, EM, Mehta, AC, Ahmad, M Bronchoscopically induced bleeding: a summary of nine years’ Cleveland Clinic experience and review of the literature.Chest1991;100,1141-1147. [CrossRef] [PubMed]
 
Maxeiner, M Lethal hemoptysis caused by biopsy injury of an abnormal bronchial artery.Chest2001;119,1612-1616. [CrossRef] [PubMed]
 
Morgan, JM Fatal haemorrhage from mycotic aneurysms of the pulmonary artery.Thorax1986;41,70-71. [CrossRef] [PubMed]
 
Gibbs, PM, Hami, A Pulmonary arterial aneurysm presenting as an endobronchial mass.Thorax1995;50,1013-1014. [CrossRef] [PubMed]
 
St Christov, V, Kanasirski, P Aneurysma des linken haupastes der arteria pulmonaris mit ruptur in den linken hauptbronchus.Zentralbl Allg Pathol1966;109,524-526. [PubMed]
 
Bowler, RP, Durham, J, Schwarz, MI Massive hemoptysis from a pulmonary artery aneurysm associated with an emphysematous bulla.Chest1998;113,1130-1131. [CrossRef] [PubMed]
 
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