Histologic Spectrum and Clinical Significance of Granulomatous Inflammation in Pulmonary Aspergillosis: A Study of 13 Cases with Comparison to Mycetomas and Invasive Aspergillosis
Jason F Back, Sanjay Mukhopadhyay. State University of New York Upstate Medical University, Syracuse, NY
Background: The significance of granulomatous inflammation in pulmonary aspergillosis is not well understood. Prior studies have suggested that granulomatous inflammation is the histologic correlate of a tuberculosis-like progressive cavitary disease known as chronic necrotizing aspergillosis. The aim of this study was to describe the histologic spectrum of granulomatous inflammation in pulmonary aspergillosis and determine its clinical significance.
Design: Biopsied or resected cases of pulmonary aspergillosis over an 11-year period (1990-2011) were reviewed. Cases that showed granulomatous inflammation were compared with mycetomas and invasive aspergillosis. Clinical, radiologic and microbiologic data were reviewed, and histologic slides re-examined with a focus on the characteristics of the inflammatory response.
Results: Granulomatous inflammation was identified in 13 patients (9 men, 4 women) ranging in age from 3 to 76 years, 7 of whom were immunocompromised (3 corticosteroids, 2 acute leukemia, 1 HIV, 1 immunoglobulin deficiency). Only 3 had a tuberculosis-like clinical picture consistent with chronic necrotizing aspergillosis. Granulomas were discovered incidentally in 3 cases. Radiographs showed lung nodules in all 9 cases in which radiologic data was available (4 bilateral, 5 unilateral). All cases showed necrotizing granulomas, with caseous necrosis in 8 and suppurative necrosis in 5. Fungal hyphae consistent with Aspergillus were identified within the necrosis in all cases. A radial arrangement of fungi, distinct from the matted arrangement of mycetomas, was noted in 8 cases. No granulomatous inflammation was seen in mycetomas (3) or invasive aspergillosis (3). Cultures were positive for Aspergillus in 4 patients. Seven patients received antifungal therapy. Of 7 patients with follow-up data (3-156 months, median 48), 3 improved, 3 showed no evidence of progression, and 1 died of progressive disease.
Conclusions: Aspergillus is occasionally found within necrotizing granulomas with caseous or suppurative necrosis within which organisms are often arrayed in a distinctive radial arrangement. Clinically, such lesions present as unilateral or bilateral lung nodules, and are often found in patients with immune deficiency, supporting the notion that they represent a form of semi-invasive aspergillosis. However, only a minority are associated with clinical features of progressive cavitary disease that can be termed chronic necrotizing aspergillosis.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 296, Tuesday Afternoon