1474. Etiology of Pulmonary Granulomas: How Common is Unsuspected Infection?

BACKGROUND: Granulomatous inflammation of the lung may be due to mycobacterial or fungal infections, sarcoidosis or vasculitis. When lung biopsy is performed due to suspicion of neoplasm, cultures may not always be done. In these cases, it is often not possible to order microbiologic testing when the pathology report is completed. The purpose of this study was to investigate how often patients with pulmonary nodules, who underwent biopsy for suspected malignancy, simultaneously have specimens sent for culture to assess for an infectious etiology. METHODS: We retrospectively reviewed the pathology reports of 36 patients from 2014 to 2015 who underwent lung biopsy of pulmonary nodules that showed granulomatous inflammation. RESULTS: Thirty-six patients underwent lung biopsy of pulmonary nodules. One patient was excluded because their pathology report did not reveal any granuloma, resulting in a final sample size of 35 patients. Of these, eight (22.9%) patients simultaneously had specimens sent for mycobacterial and fungal cultures while the other 27 (77.1%) did not. Of the 27 patients who did not have specimens simultaneously sent for mycobacterial and fungal cultures, 17 (48.6% of the sample size) were diagnosed with lung cancer. The remaining 10 (28.6% of the sample size) patients did not have a definitive diagnosis because cultures were not sent for testing (Figure 1). Of the eight patients with cultures sent for testing, two (25%) had pulmonary tuberculosis, four (50%) had nontuberculosis mycobacterium infections, and two (25%) had fungal infections (one was Cryptococcus and one had mixed Aspergillus and Penicillium) (Figure 2). CONCLUSION: We conclude that pulmonary nodules may have an infectious etiology when biopsy is performed for a suspected malignancy. Specimens should routinely be sent for mycobacterial and fungal cultures regardless of presumptive diagnosis. DISCLOSURES: All authors: No reported disclosures.