Bone marrow granulomatosis: two case reports

Bone marrow granulomatosis is not a common finding and remains a diagnostic challenge. Here below we report two bizarre but not so rare cases of bone marrow granulomatosis: bone marrow involvement by Mycobacterium avium-intracellulare and reaction to intravesical administration of Bacillus Calmette-Guérin for non-muscle-invasive bladder cancer; two distinct culprits suggesting the wide range of possible causative factors of this histopathological pattern. In the discussion we provide a brief overview of causes and suggestions for a diagnostic approach.