A 9-year-old female patient presented with pain and swelling in the left foot. Her medical history revealed an episode of back pain, with duration of several months that spontaneously resolved. Laboratory tests were unremarkable. Bone biopsies of the 2nd metatarsal bone of left foot demonstrated sub-acute, non-infectious, inflammatory changes.
Radiography demonstrated a lytic lesion of the distal metaphysis of the 2nd metatarsal bone of the left foot associated with ground glass heterogeneity of the adjacent diaphysis and a thick single layer of periosteal reaction (Fig. 1). Whole-body imaging was performed using Tc99m scintigraphy (Fig. 2), and whole-body MRI (WBMRI) (Fig. 3). EOS was performed to investigate spinal localisation of disease, in particular, secondary scoliosis (Fig. 5). Similar lesions were found in the D5-D6 vertebra (with loss of vertebral height) and the 12th left rib. All lesions were associated with soft tissue oedema without abscess formation on MRI.
At follow-up, EOS showed amelioration of the D5-D6 vertebra height under contention (Fig. 6). WBMRI revealed decreased peri-vertebral tissue and marrow oedema of the metatarsal bone. However, we noticed increased hyperostosis and oedema of the 12th left rib. Two new disease localisations were detected in the left and right tibial metaphysis (Fig. 4).
Chronic recurrent multifocal osteomyelitis (CRMO) is a non-infectious recurrent osteomyelitis usually seen in children and young adults (M : F = 1 : 2, 1 ; mean age 10y) [5]. The origin remains unclear but appears to be associated with autoimmune disease and genetic predisposition.
Clinically, patients present with systemic symptoms (low fever, malaise), cutaneous symptoms (palmo-plantaris pustulosis, psoriasis, acne), pain, and soft tissue oedema associated with the bony lesion. The most frequent localisations are the tubular bones, clavicles, ribs, spine and pelvis. A bone biopsy is necessary to exclude malignant and infectious lesions and demonstrates signs of acute, sub-acute and chronic osteomyelitis.
Imaging findings initially show lytic lesions surrounding by a sclerotic rim with soft tissue oedema. These lesions evolve towards sclerosis and hyperostosis and usually heal completely [1]. However, each site of disease evolves independently resulting in different imaging characteristics. Rare complications include early fusion of growth cartilage. Usually, only symptomatic treatment is available.
The aim of imaging studies is to evaluate clinically symptomatic and occult sites of disease [6, 7]. Traditionally, symptomatic locations are explored by radiography and Tc99m scintigraphy for whole-body examination. However, MRI is becoming more and more common because of its non-irradiating properties [2]. WBMRI allows identification of all disease localisations and adds important information such as the extent and progress of metaphyseal involvement in patients who could be at risk of early growth cartilage fusion leading to limb length abnormalities [4]. The addition of EOS for diagnosis and follow-up of vertebral fractures can decrease radiation dose even further [3]. However, aside from its role in scoliosis management, its role in disease follow-up remains to be investigated.
Chronic recurrent multifocal osteomyelitis
In this case, the X-ray of the patient’s left second metatarsal shows localized bone changes, manifested as mixed lytic lesions with sclerotic margins, along with surrounding soft tissue swelling. A whole-body bone scan suggests increased radiotracer uptake in the thoracic vertebrae, ribs, and other locations, indicating similar lesions. Whole-body MRI (WBMRI) further confirms multiple abnormal bone marrow signals in the spine and certain long bones, presenting as subacute inflammatory changes without obvious abscess or tumor-like erosion. Overall, these imaging findings are consistent with multifocal, non-infectious, recurrent osteitis.
Based on the patient’s age, the typical subacute and recurrent course of osteitis, the multifocal inflammatory lesions shown on imaging, and bone biopsy results demonstrating non-infectious inflammation, the most likely diagnosis is Chronic Recurrent Multifocal Osteomyelitis (CRMO).
For CRMO, which is associated with autoimmune or autoinflammatory reactions, the primary treatment goal is to control symptoms and prevent skeletal deformities:
Regarding rehabilitation exercises, an individualized and gradual FITT-VP approach is recommended:
When implementing rehabilitation, pay attention to potential bone fragility and fatigue due to recurrent osteitis. Ensure adequate protection of affected joints or skeletal structures during exercises, monitor symptom changes closely, and progress gradually.
The above report is solely based on the current clinical and imaging information available and serves as a reference. It does not replace a face-to-face medical evaluation or professional diagnosis and treatment. If you have any questions or changes in symptoms, please consult an orthopedic specialist or other relevant medical professionals promptly.
Chronic recurrent multifocal osteomyelitis
