[1342] Infectious Etiology of Granulomatous Inflammation on Bone Marrow Biopsy

SS Rahman, JM Ben-Ezra. Virginia Commonwealth University Health System, Richmond, VA

Background: Bone marrow aspiration and biopsy are commonly performed in evaluation of immunocompromised patients, especially those with AIDS/HIV. Granulomatous inflammation is identified in a subset of these biopsy cases, which consequently warrants further workup for an infectious source with histochemical stains or microbiological cultures. The infectious etiology of the granulomatous inflammation seen on bone marrow biopsy is not fully understood.
Design: We conducted a retrospective review of all adult bone marrow biopsies obtained from January 2000 through June 2008 in which both microbiological cultures of the bone marrow aspirate were collected and histochemical stains for microorganisms (GMS, PAS-Light Green, Ziehl-Neelsen) were performed. The following characteristics for each case were recorded: age, gender, HIV status and viral load, biopsy length and width, presence or absence of granulomatous inflammation, and results of histochemical stains and microbiological cultures.
Results: A total of 113 cases meeting the above criteria were reviewed. Granulomatous inflammation was identified in 47 cases (41.6%), of which 17 cases (36.2%) showed evidence of infection by either histochemical stain or microbiologic culture. Conversely, infection was detected by stain or culture in 9 out of 66 cases (13.6%) without granulomatous inflammation (p=0.005). Of the 113 cases studied, 10 cases (8.9%) were positive for microorganisms by both histochemical stains and culture; 12 cases (10.6%) were culture-positive, stain-negative; 4 cases (3.5%) were stain-positive, culture-negative; and 87 cases (77.0%) were culture-negative, stain-negative (p<0.001). The organisms identified by culture were Mycobacterium avium complex (19 cases), Histoplasma capsulatum (2 cases), and Cryptococcus neoformans (1 case). There was no significant relationship between biopsy area (length x width) and granulomatous inflammation (p=0.318). In addition, there was no correlation between HIV status (+/-) and either granulomatous inflammation (p=0.114) or detection of microorganisms (p=0.147). There also was no correlation between HIV viral load and presence of granulomas (p=0.404) or infection (p=0.584).
Conclusions: The presence of granulomatous inflammation on bone marrow biopsy is associated with fungal or mycobacterial infection in a minority of cases (36.2% in our series). A combination of both histochemical stains and microbiological culture of the aspirate material is recommended for enhanced detection of occult microorganisms in immunocompromised patients.
Category: Infections

Monday, March 9, 2009 11:00 AM

Platform Session: Section G 2, Monday Morning