Clinical and pathological feature of bone marrow granulomas: A modern Australian series

Introduction: Marrow granulomas have been commonly associated with mycobacterial infections, prompting extensive investigations in some cases where they are found, but in the setting of changing infectious epidemiology, there is a lack of recent data to guide the search for probable causes. Methods: A retrospective case series examining the clinical and pathological findings in all cases where marrow granulomas were reported over a 10-year period at The Canberra Hospital, Australia. Results: Of the 6062 marrow biopsies performed, 73 (1.2%) from 66 individuals had confirmed granulomas. Some patients had multiple potential causes found. B-cell non-Hodgkin Lymphoma, sarcoidosis and autoimmune disease were the most frequently observed causes. Infections were less common in this cohort than in the previous series, with no tuberculosis seen. The presence of granulomas in the marrow did not signify the presence of active malignancy in the marrow. There were no associations with any specific morphological characteristics of the granulomas and the presumed causes. Conclusion: Marrow granulomas are seen in a variety conditions. Neither their presence nor their morphological features are a guide to further investigations, which should be determined by the clinical presentation as appropriate.