Chronic multifocal osteomyelitis: is infectious causation a moot point?

Chronic multifocal osteomyelitis (CMO) is an uncommon disease entity with descriptions possibly emanating from the medical literature over one century ago, and there are numerous disease entities which have been historically detailed and which are probably synonymous. The illness is one of chronicity with exacerbating and remitting focal bony lesions. The differential diagnosis for a bony lesion which ultimately proves to be CMO is initially quite broad. There is no absolute pathognomonic clinical finding, and the diagnosis is highly dependent on clinical course, histopathology, and an absence of microbial infection. Recent studies have focused on immune dysfunction or dysregulation, and there are now many other diseases which are inflammatory in nature and which have been diagnosed among patients with CMO. Despite the aforementioned, the potential for direct infectious causation or indirect causation by infectious stimulation of immunity cannot be entirely excluded. Infection as a mechanism for pathogenesis must continue to be entertained. Multi-centre studies are key to future research.