1394. Clinicopathologic Features of Infectious and Noninfectious Tissue Granulomas in Transplant Patients

Abstract Background There is a paucity of literature about the implications of granulomatous disease in hematopoietic stem cell transplant (HSCT) and solid-organ transplant (SOT) patients. Given the broad range of infectious and noninfectious etiologies as well as the heightened risk for severe infection, it is important to characterize the clinicopathologic features of granulomas in this population and to develop a framework to guide further evaluation. Methods We performed chart reviews of 1,280 transplant recipients (791 SOT and 489 HSCT) at Yale-New Haven Hospital from 2009 to 2019 to identify patients with granulomas in pathologic specimens obtained peri-transplantation. Data on histopathology, microbiology, indication for biopsy, patient characteristics, and clinical presentation were recorded. Morbidity and mortality were noted at 1, 3, and 12 months after granuloma diagnosis. Results We identified 28 patients with granulomas (9 SOT, 19 HSCT); an incidence of 2.2%. None had explicit risk factors for MTB. Most granulomas (93%) were non-necrotizing. Common sources were lung (n = 9) and lymph node (n = 5). Most were found post-transplant (n = 19) and biopsies were prompted mostly by symptoms (n = 13) or incidental imaging findings (n = 9). Most granulomas were not associated with an infectious process (n = 20). Among infectious granulomas, bacterial soft-tissue infection (n = 2), bartonellosis (n = 2), and fungal infection (1 Cryptococcus and 1 Blastomyces) were most common. MTB PCR was negative in 4 specimens. Among granulomas discovered in SOT patients, 44% were infectious compared with 21% in HSCT recipients. Most infectious granulomas were found in symptomatic patients (75%). One granuloma-related adverse outcome occurred in a case of cryptogenic organizing pneumonia discovered pre-HSCT that worsened with tapering of immunosuppression post-HSCT. Conclusion Granulomas were uncommon in a large transplant population. Most were deemed noninfectious and their presence alone was not associated with adverse outcomes post-transplant or with increased immunosuppression. Granulomas were more likely to be infectious in SOT recipients and those with symptoms. Symptoms should guide the extent of microbiologic evaluation and reflexive MTB PCR testing is not warranted if risk factors are absent. Disclosures All authors: No reported disclosures.