Ann Thorac Surg 2009;88:1352-1354. doi:10.1016/j.athoracsur.2009.02.087
© 2009 The Society of Thoracic Surgeons
Case Reports
An Unusual Case of Aspergillus Fibrosing Mediastinitis
Sean C. Wightman, BAa,
Anthony W. Kim, MDa,
Laurie A. Proia, MDb,
L. Penfield Faber, MDa,
Paolo Gattuso, MDc,
William H. Warren, MDa,
Michael J. Liptay, MDa,*
a Division of Thoracic Surgery, Rush University Medical Center, Chicago, Illinois
b Section of Infectious Disease, Rush University Medical Center, Chicago, Illinois
c Department of Pathology, Rush University Medical Center, Chicago, Illinois
Accepted for publication February 20, 2009.
* Address correspondence to Dr Liptay, Division of Thoracic Surgery, Rush University, 1725 West Harrison St, Suite 774, Chicago, IL 60612 (Email: michael_liptay{at}rush.edu).
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Abstract
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Fibrosing mediastinitis due to Aspergillus is rare, particularly in the immunocompetent host. Fibrosing mediastinitis due to Aspergillus species in the immunocompetent patient can be indolent and may be treated with antifungal therapy rather than surgery. We present a 78-year-old nonsmoking, nondiabetic woman with chronic fibrosing mediastinitis due to Aspergillus. Multiple attempts at securing a tissue diagnosis were inconclusive. Ultimately, Aspergillus infection was diagnosed by a video-assisted thoracoscopic surgical biopsy. The patient was started on oral voriconazole, and she remains clinically stable with radiographic improvement. A prolonged, perhaps lifelong, course of antifungal therapy is planned.
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Introduction
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Fibrosing mediastinitis due to Aspergillus is rare, particularly in the immunocompetent host. Fibrosing mediastinitis due to Aspergillus species in the immunocompetent patient can be indolent and may be treated with antifungal therapy rather than surgery. We present a 78-year-old nonsmoking, nondiabetic woman with chronic fibrosing mediastinitis due to Aspergillus, and we describe the clinical course and medical management of this uncommon infection.
A 78-year-old woman without a significant past medical history presented to an outside hospital with cough and hemoptysis 5 years ago. Treatment with an oral antibiotic for presumed community acquired pneumonia relieved her symptoms, but a right lower lobe infiltrate persisted on chest roentgenogram. A computed tomographic (CT) scan demonstrated right lower lobe pneumonitis with lymphadenopathy, and 2 months later a repeat CT scan was unchanged. However, a third serial CT scan performed 5 months after the initial scan revealed a hilar mass, a two centimeter lymph node in the right hilar region, and a nodule in the right lower lobe surrounded by patchy infiltrates (Fig 1). A positron emission tomographic scan and a CT scan demonstrated increased activity in the right hilar mass, along with mild activity in the right lower lobe. One year later the patient was referred to our institution, and a flexible bronchoscopy with biopsy was inconclusive. Histopathology showed reactive epithelial cells without evidence of neoplasm; no cultures were sent at that time. Three months later, the patient underwent a fine-needle aspiration and core needle biopsy of the right lung mass. These findings were also nondiagnostic; histopathology showed no neoplastic cells or granulomas, and special stains for micro-organisms, including fungi, were negative.
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Fig 1. An infiltrating mass in the right infrahilar region. The arrow shows an edge of the mass. (DA = descending aorta; LA = left atrium; RA = right atrium.)
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During this time, the patient remained asymptomatic without fever, cough, or chest pain. However, serial CT scans demonstrated progression in size of the ill-defined, lower right hilar mass with encasement of the right lower lobe bronchus, inferior pulmonary vein, and encroachment on the left atrium. Endoscopic ultrasound with biopsy was attempted but was deemed too risky due to the encasement of the left atrium. A repeat CT scan showed a mass (4.8 cm) along the posterolateral wall of the left atrium. This mass extended anteriorly, encompassing the ascending aorta, compressing the superior vena cava, and severely encompassing and narrowing the right mainstem bronchus. The paratracheal and subcarinal lymph nodes were enlarged, and the right lower lobe nodule was still present (Fig 2).
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Fig 2. The shown hilar infiltrate extends into the interatrial septum, encompasses the right atrium, and also partially encases the ascending aorta. The arrows show edges of the mass. (DA = descending aorta; LA = left atrium; RA = right atrium.)
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The patient ultimately underwent a video-assisted thoracoscopic surgical biopsy of the mediastinal mass. Histopathologic examination was negative for malignancy, but revealed granulomatous inflammation. A Gomori methenamine silver stain highlighted fungal hyphae. Fungal culture of the mediastinal mass grew a mold on two of three plates after 3 days of incubation, which was later identified as Aspergillus flavus. On further questioning, the patient reported being a nonsmoker who lives alone in a suburb outside of Chicago. She denied any obvious evidence of mold in the bathroom, attic, or basement of her home. She was not aware of any construction in her neighborhood but does like to garden outdoors.
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Comment
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Aspergillus, a mold found throughout the environment, may cause invasive disease in the immunocompromised host, but it is a rare pathogen in the immunocompetent individual [1–3]. The most common manifestation of invasive aspergillosis is pneumonia, because the lungs serve as the main portal of entry for inhaled spores [4]. Although there are many causes of fibrosing mediastinitis, most cases are usually due to the immunologic reaction to the antigens of Histoplasma, also found throughout the environment. Mediastinal aspergillosis may result from a primary Aspergillus pneumonia that spreads to adjacent mediastinal structures [5]. Most of the reported cases of Aspergillus mediastinitis are caused by Aspergillus fumigatus and occur in the pulmonary arteries, the heart, or the aorta [1].
The first reported case of Aspergillus flavus causing granulomatous mediastinitis was in 1981. A 22-year-old immunocompetent man presented with cough, fever, and a right hilar mass. Mediastinal biopsies revealed Aspergillus flavus. The patient was treated with amphotericin B and 5-fluorocytosine, but expired after esophageal and superior vena caval compression [3]. Another case published in 1984 described chest wall invasion by Aspergillus flavus in a 24-year-old healthy, immunocompetent man. After Aspergillus flavus was confirmed on biopsy, amphotericin B therapy resulted in complete resolution of the infection [6].
It is interesting to note that our patient had an atypical course of chronic mediastinal aspergillosis as evidenced by chest roentgenograms and CT scans obtained within 5 years. Although the infection progressed during the 5 years, the patient remained essentially asymptomatic during that time. It is plausible that Aspergillus was the cause of her initial right lower lobe pneumonia, because the infiltrate evolved into a right lower lobe nodule and then subsequently progressed to a right hilar mass with ipsilateral adenopathy. Because our patient is presumed to be immunocompetent, it is possible that her immune system was able to partially control the infection during this period of time. This is distinctly different from the typical pattern of Aspergillus infections in immunocompromised patients, which is usually rapidly progressive [2]. Despite our patient's lack of symptoms, the growth of the mediastinal mass was troublesome and a definitive tissue diagnosis was needed. Using the video-assisted thoracoscopic surgical approach, adequate tissue specimens were obtained directly from the mass to reveal fungal hyphae and Aspergillus flavus in the tissue culture.
Optimal treatment of Aspergillus mediastinitis is unclear because of the infrequent number of reported cases. The few published reports have shown the benefit of combined surgical and medical therapy [7]. Our patient did not receive surgical debridement owing to the extensive involvement of mediastinal structures. She was started on oral voriconazole, 200 mg twice daily, with monitoring of serum concentrations. Voriconazole, an extended spectrum triazole antifungal, is recommended as a first-line therapy for infections caused by Aspergillus [4]. The patient continues to do well clinically and radiographically, with no evidence of disease progression after 6 months of treatment with voriconazole. The exact duration of antifungal treatment is unknown, but is likely to be necessary indefinitely.
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References
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- Taouli B, Cadi M, Leblond V, Grenier PA. Invasive aspergillosis of the mediastinum and left hilum: CT features Am J Roentgenol 2004;183:1224-1226.[Free Full Text]
- Wells WJ, Fox AH, Theodore PR, Ross LA, Stanley P, Starnes VA. Aspergillosis of the posterior mediastinum Ann Thorac Surg 1994;57:1240-1243.[Abstract/Free Full Text]
- Ahmad M, Weinstein AJ, Hughes JA, Cosgrove DE. Granulomatous mediastinitis due to aspergillus flavus in a nonimmunosuppressed patient Am J Med 1981;70:887-890.[Medline]
- Walsh TJ, Anaissie EJ, Denning DW, et al. Treatment of Aspergillosis: clinical practice guidelines of the Infectious Diseases Society of America Clin Infect Dis 2008;46:327-360.[Free Full Text]
- Pasqualotto AC, Denning DW. Post-operative aspergillosis Clin Microbiol Infect 2006;12:1060-1076.[Medline]
- Jordan JM, Waters K, Caldwell DS. Aspergillus flavus: an unusual cause of chest wall inflammation in an immunocompetent host J Rheumatol 1986;13:660-662.[Medline]
- Vandecasteele SJ, Boelaert JR, Verrelst P, et al. Diagnosis and treatment of Aspergillus flavus sternal wound infections after cardiac surgery Clin Infect Dis 2002;35:887-890.[Abstract/Free Full Text]
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Abstract
Introduction
