E1363. Multimodality Imaging Features of Chronic Recurrent Multifocal Osteomyelitis (CRMO)/Chronic Nonbacterial Osteomyelitis (CNO)
  1. Aparna Tompe; Geisinger Medical Center
  2. Kiran Sargar; Geisinger Medical Center
  3. George Wu; Geisinger Medical Center
Chronic recurrent multifocal osteomyelitis or chronic nonbacterial osteomyelitis is a rare noninfectious inflammatory disorder in children that primarily affects the bones and can cause osseous destruction if untreated. It is necessary to distinguish CRMO/CNO from infectious osteomyelitis and neoplasms.

Educational Goals / Teaching Points
To demonstrate multimodality imaging features of CRMO/CNO in children in a case-based format and to discuss key imaging features to differentiate CRMO/CNO from infectious osteomyelitis and neoplasms.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
CRMO/CNO can affect children of all ages, with a peak onset between 7 and 12 years and female predominance. CRMO/CNO most commonly affects metaphyses of long bones, clavicle, mandible, vertebrae and pelvis. In this presentation, we will highlight radiographic, MRI, CT and nuclear scan imaging features of CRMO/CNO. On imaging, multifocal lytic and sclerotic lesions are seen in metaphyses of long bones, clavicles and mandible. There are two phases of CRMO –active and reparative. The lytic lesions are more common in active phase and sclerotic lesions and hyperostosis are common in reparative phase. In spine, CRMO involves multiple noncontiguous vertebral bodies with sparing of intervertebral disc. Typically infectious osteomyelitis causes unifocal involvement, while multifocal involvement is more common in CRMO/CNO. Though extremity involvement is common in CRMO, involvement of clavicles and mandible is important differentiating point between CRMO and infectious osteomyelitis. Lack of abscess ,fistula, sequestrum, significant soft tissue involvement and aggressive periosteal reaction are the key features to differentiate CRMO from infectious osteomyelitis and neoplasms.

The knowledge of key imaging features of CRMO/CNO is helpful for the radiologist to suggest this uncommon diagnosis. Differentiation of CRMO/CNO from infectious osteomyelitis and neoplasms is essential for appropriate management and prognostication.