Chronic diffuse sclerosing osteomyelitis (CDSO) is a rare, non-suppurative mandibular condition that often mimics infectious osteomyelitis (IO), making diagnosis and management challenging. This study aimed to identify key clinical, radiological, histopathological, and therapeutic features distinguishing CDSO from IO and to propose a diagnostic and treatment strategy.

We conducted a retrospective descriptive study of 43 patients treated for mandibular osteomyelitis at Nantes University Hospital between 2007 and 2020. Clinical records, imaging, histological and microbiological data, and treatment outcomes were analyzed and compared between patients diagnosed with CDSO and those with IO.

CDSO affected mainly middle-aged women and showed a high recurrence rate despite prolonged antibiotic use. It was characterized by mononuclear infiltrates, medullary fibrosis, and bone condensation without abscess formation. In contrast, IO showed neutrophilic infiltrates, bacterial clusters, and osteolysis often with soft tissue abscesses. Antibiotics were effective in IO but frequently failed in CDSO. Anti-inflammatory and rheumatologic treatments, including NSAIDs, corticosteroids, bisphosphonates, and biotherapies, showed variable but encouraging responses in CDSO. Imaging differences, particularly on CBCT and CT, helped differentiate the two entities.

This study highlights the need for a multidisciplinary approach, including rheumatologic expertise, in the management of CDSO. The lack of gold standard diagnostic criteria complicates classification, yet histopathology and radiology provide helpful orientation. Larger prospective studies are warranted to validate our findings and optimize treatment protocols for CDSO.