Introduction: Granulomatous lesion in the bone marrowis not a common finding and can be attributed to a variety of conditions ranging from infections to malignancies to drugs. Though tuberculosis is the most common etiology, bone marrow granulomas can be associated with a number of infections and other non infective conditions. The incidence of bone marrow granulomas has been increasing over the years due to the increasing surge of HIV infection. Aims: This study basically aims to study the prevalence of bone marrow granulomas, to identify the various causes and to study the pattern of granulomas in different conditions. Materials & Methods: This is a retrospective analysis of 100 cases of bone marrow granulomas conducted in the Clinical Laboratory of Kasturba hospital for a period of four and a half years from January 2009 to May 2013.The clinical details were collected from medical records and bone marrow biopsy slides were retrieved and studied. Results: Out of the 100 cases, 66% cases were diagnosed as tuberculosis. 17% cases were due to other infections like Typhoid fever (5%), Brucellosis (4%), Scrub typhus (2%), Hansen’s disease (1%), Cryptococcosis (2%) and HIV infection itself without any other opportunistic infections (3%). Malignancies accounted for 9% cases, Sarcoidosis (1%) and in 7% cases a definitive diagnosis was not reached. Among the 66 cases of tuberculosis, 40 (60%) cases were immunodeficient due to HIV infection. HIV positive cases predominantly showed single (52%), ill defined granulomas (73%), with caseation necrosis (52%), while HIV negative cases predominantly showed single (54%), small (50%), well defined or ill defined granulomas with plump epithelioid cells (58%) and Langhans giant cells (42%). Conclusion: There can be varied etiology for bone marrow granulomas with tuberculosis being the most common cause.The morphology and pattern of granulomas can aid in the diagnosis of the condition hence study of bone marrow for granulomas should be considered as an important diagnostic tool in such conditions.

Keywords: Bone Marrow; Granuloma; Tuberculosis; HIV; Drugs; Morphology.