Fig. 3A & 3B:PA (Fib. 3A) and lateral (Fig. 3B) views of the left wrist show a lobulated osteolytic lesion with well-defined borders and surrounding sclerosis in the distal radius. Minimal expansion, mild periosteal reaction and soft tissue swelling are present.
Fig. C and D
Fig. E
Fig. 3C,3D,3E: AP (Fig. 3C ) and lateral (Fig. 3D) radiograph of right tibia and fibula and lateral (Fig. 3 E) radiograph of the right calcaneus, ten months later. Multiple well-defined osteolytic lesions involving the proximal diaphysis of the tibia are identified within a broad border of sclerosis (arrows). A similar lesion is identified within the posterior calcaneus near the physis of the posterior apophysis (Fig. 3E). No significant periosteal reaction is present.
Discussion: Chronic recurrent multifocal osteomyelitis (CRMO) is an uncommon subacute and chronic osteomyelitis of childhood of unknown etiology. Similar radiographic and clinical findings have been variably described as subacute symmetric osteomyelitis, chronic multifocal cleidometaphyseal osteomyelitis, plasma cell osteomyelitis, and as part of the SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome. CRMO is characterized by multiple relapsing symptoms and is a self-limited process with minimal residual sequelae. A female predilection exists for this disease, and it is most commonly seen in children and adolescents. However, the age of onset has ranged from 20 months to 55 years (1). The characteristic course of exacerbation and remission typically lasts several years (2-4).
The clinical manifestations include pain, focal tenderness and erythema over the region of osteomyelitis. Mild fever and minimal systemic symptoms are present. Arthralgia and skin changes of palmoplantar pustulosis and psoriasis are described in association with this condition. The laboratory findings include an elevated erythrocyte sedimentation rate with a normal or minimally elevated white blood cell count. Bone biopsy shows changes of osteomyelitis with varying degrees of fibrosis and plasma cell, lymphocyte and histiocyte infiltration. Both the bone and blood cultures are negative for pathogens. No association with an immune deficient state has been established.
The tibia, fibula, femur, and clavicle are the most common sites of involvement. The radius, ulna, foot and vertebra are also frequently involved (2,3,5). The lesions are often but not always symmetrical. Similar to the sites of involvement of acute hematogenous osteomyelitis in children and infants, the metaphysis of long bones are most commonly involved. Initially, a well-defined osteolytic lesion with a pyramidal shape or sinuous border is identified near the physis. A thin rim of sclerosis may be seen (3). Later, extensive peripheral sclerosis develops which is characteristic of this disease. Frequently, there is associated soft tissue swelling. Periosteal reaction is minimal if present at all. Although most lesions heal completely, some lesions leave residual sclerosis and expansion (2). The smaller diameter bones, such as distal radius and ulna, distal fibula, clavicle and ribs, present with more extensive periosteal reaction, sclerosis and soft tissue swelling compared to the large diameter bones (6). Although most lesions typically resolve without clinical sequelae, occasionally epiphyseal extension may cause premature physeal fusion (3,6). In addition, sclerosis and expansion around joints can predispose to future development of degenerative joint disease (4). A vertebral lesion causing vertebra plana and progressive kyphosis has been described (2).
While the hallmark of radiographic diagnosis rests with plain film imaging, radionuclide bone scintigraphy can help locate additional lesions. Recently, MRI findings of CRMO have been described (7,8). As expected with most inflammatory processes, the T1-weighted images demonstrate decreased signal and T2-weighted images demonstrate increased signal in comparison to normal marrow signal (7,8). With the progression of the disease conversion to decreased signal on T2-weighted images is described (7).
The differential diagnosis for the multifocal osteolytic lesions of CRMO in the pediatric population would include bacterial osteomyelitis, histiocytosis X (eosinophilic granuloma, Langerhan’s histiocytosis), leukemia and metastatic neuroblastoma. Once a biopsy diagnosis confirms the absence of malignancy or culture positive osteomyelitis, CRMO should be the primary consideration. Diagnostic criteria for CRMO have been proposed to include all of the following: (a) the presence of two or more radiographically confirmed bone lesions, (b) a prolonged course of at least 6 months with characteristic exacerbation and remission, (c) radiographic and nuclear scintigraphic evidence of osteomyelitis, (d) a lack of response to antimicrobial therapy of at least 1 month’s duration, and (e) the lack of an identifiable etiology (6). A definitive role for steroids or long term antibiotics has not been established. Supportive management with anti-inflammatory medication is recommended, as the typical course of CRMO is self-limited.
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osteomyelitis with MR correlation: A case report. Pediatr Radiol 1992:22:535-536.
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