SESSION TITLE: Interstitial Lung Disease Posters I
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM
PURPOSE: Granulomatous lung disease (GLD) is caused by inflammatory, infectious, and autoimmune conditions. GLD has a distinctive histologic pattern of a chronic inflammatory reaction characterized by focal accumulation of activated macrophages with or without necrosis. Often there is a need to correlate pathological findings with clinical, microbiologic or radiologic data to determine an etiology. The purpose of this study was to determine the different etiologies of GLD over a 10-year period.
METHODS: 2228 consecutive lung specimens were evaluated from 1999 to 2011. 226 cases (10.1%) were positive for GLD. 190 cases were retrospectively reviewed and diagnoses were assigned based on availability of histologic/clinical/microbiologic data.
RESULTS: A confident, probable and uncertain diagnosis was made in 68.4%, 13.2% and 18.4% the 190 cases evaluated. The etiologies were determined to be infectious, non-infectious and uncertain in 104 (54.7%), 51 (26.8%) and 35 (18.4%) of the cases. Mycobacterial infections represented 52/190 (27%), with atypical pathogens being the most common 24/52 (50%). Acid-fast bacilli were visualized in tissue sections in 15/52 (29%) cases, and cultured in 38/52 (73%) cases. Fungal infections were identified in 52/190 (27%), which included Coccidioides, Cryptococcus, Aspergillus, and Histoplasma in order of frequency. Fungi were visualized in tissue sections with GMS stain in 42/52 (83%) cases, and cultured in 27/52 (52%) cases. Sarcoidosis was the most common non-infectious etiology, constituting 39/190 (21%) of all cases. Necrosis in granulomas was associated with the presence of infection (p<0.001).
CONCLUSIONS: An infectious etiology of is the most common cause of GLD in this study. Atypical mycobacteria were the most common bacterial pathogens identified. Coccidioidomycosis was the most common fungal infection. The etiology in non-necrotizing GLD, is most likely non-infectious, and most frequently sarcoidosis.
CLINICAL IMPLICATIONS: It is critical to reach the precise etiology of GDL because the treatment may differ significantly, ranging from induced immunosuppression (i.e. sarcoidosis) to aggressive antibiotic therapy (i.e tuberculosis). Mycobacterial and fungal infections, and sarcoidosis figure prominently as causes of GLD. This study provides further epidemiological data on the most common infectious and non-infectious causes of GLD, which may aid those who encounter this condition in clinical practice.
DISCLOSURE: The following authors have nothing to disclose: Alia Nazarullah, Victor Kha, Diego Maselli, Robert Nilson, Jaishree Jagirdar
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