Imaging of chronic recurrent multifocal osteomyelitis

Comparative study of radio-clinical parameters in pediatric forms of fibrous dysplasia and chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disease with clinical and radiological symptoms that overlap with fibrous dysplasia (FD), particularly in children. This study aimed to compare the clinical and radiological features of craniofacial CRMO and FD in a pediatric population. Seven children with CRMO and 14 with FD were retrospectively identified in our tertiary centre between 2012 and 2022. Their clinical, radiological, and biological (when available) data were collected. Two experienced radiologists reviewed imaging modalities following a standardized form, including characteristics of the lesions, soft-tissue involvement, and signal abnormalities (MRI). Swelling and pain were common symptoms in the CRMO group (7/7 and 5/5, respectively), compared with 11/14 and 2/14 patients in the FD group. Imaging (CT scan) comparisons revealed a predominance of erosive lesions, cortical interruption, periosteal apposition, and soft-tissue involvement in CRMO compared with FD (4/5 vs 0/6, p1 = 0.01; 5/5 vs 1/6, p2 = 0.01; 5/5 vs 0/6, p3 = 0.002; and 4/5 vs 0/6, p4 = 0.02, respectively). Hyperosteosis was mainly associated with FD lesions (6/6 vs 2/5, p = 0.06). Knowledge of the clinical and radiographic differences between CRMO and FD could help clinicians to differentiate between the two diseases.

Whole-body Magnetic Resonance Imaging in Inflammatory Spine and Joint Disease

Whole-body magnetic resonance imaging (WB-MRI) can effectively diagnose rheumatologic diseases with systemic and multifocal characteristics, such as spondyloarthritis, chronic recurrent multifocal osteomyelitis, and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, among others. Advances in rheumatic disease treatments have emphasized the importance of early diagnosis for effective management, function preservation, and improved quality of life. WB-MRI offers comprehensive imaging of the musculoskeletal system, detecting early and subtle disease changes that traditional methods might overlook. Initially used for spondyloarthritis, the technique has recently expanded to other rheumatic diseases and is becoming the gold standard for diagnosing and monitoring chronic nonbacterial osteomyelitis in pediatric patients. This review article presents the current status of WB-MRI in rheumatologic conditions.

Incidence of chronic recurrent multifocal osteomyelitis in children and adolescents in the UK and Republic of Ireland

OBJECTIVES

Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic non-bacterial osteomyelitis (CNO), is a rare autoinflammatory condition affecting the bones in children and teenagers. The actual incidence of CRMO remains uncertain. The objective of this study was to identify the incidence of CRMO in children and young people under the age of 16 years in the United Kingdom (UK) and Republic of Ireland (ROI). We also aimed to delineate the demographics, clinical presentation, investigations, initial management and healthcare needs for children and adolescents with CRMO.

METHODS

We conducted monthly surveys among all paediatric consultants and paediatric orthopaedic surgeons to identify patients newly diagnosed with CRMO between October 2020 and November 2022. A standardized questionnaire was sent to reporting clinicians to collect further information.

RESULTS

Over the surveillance period, 288 patients were reported, among which, 165 confirmed and 20 probable cases were included in the analysis. The highest incidences were among 8-10 year-olds. A two-to-one female-to-male difference in incidence was observed, and male patients were more likely to present with multifocal disease. A negative correlation was observed between reporting clavicular and leg pain. Investigation-wise, 80.0% of patients were reported to have undergone whole-body MRI and 51.1% had bone biopsies. The most common initial treatments were NSAIDs (93.9%) and bisphosphonates (44.8%).

CONCLUSION

This study estimates an average annual CRMO incidence of 0.65 cases per 100 000 children and adolescents in the UK and ROI. These findings establish a crucial baseline for ongoing research and improvement in the care of individuals with CRMO.

Challenges in the imaging and diagnosis of chronic non-bacterial osteomyelitis (CNO)

Chronic non-bacterial osteomyelitis (CNO) is a benign skeletal disorder of childhood and adolescence characterised by sterile bone inflammation that results in chronic insidious bone pain. Although it is increasingly recognised, many challenges remain in its diagnosis with patients waiting 15-24 months for diagnosis from the time of symptom onset. Prompt identification and treatment are key to reducing morbidity from CNO, which affects school attendance and can result in chronic limb or spine deformities. Identifying its imaging features, particularly its characteristic lesion distribution on whole-body MRI, remains key to diagnosis. Image-guided biopsy is also required in many cases, particularly those with clinical uncertainty around the diagnosis. We present a review of the challenges encountered in the diagnosis of CNO from a critical appraisal of the literature and our experience as a national paediatric sarcoma, rheumatology and orthopaedic centre. This review hopes to inform radiology colleagues involved in the evaluation of potential CNO patients by discussing its imaging appearances, typical MRI phenotypes, potential mimics and the role of image-guided biopsy.

Whole-Body MRI in Children: Concepts and Controversies-AJR Expert Panel Narrative Review

The use of whole-body MRI (WBMRI) in children, from infancy to adolescence, has expanded rapidly over the past decade, with increasing uptake and a broadening range of clinical indications. Current indications include screening for presymptomatic lesions in cancer predisposition syndromes; tumor staging in known malignancies; investigating fevers of unknown origin; as well as diagnosing and monitoring rheumatologic diseases, vascular anomalies and neuromuscular disorders. This AJR Expert Panel Narrative Review aims to offer a comprehensive discussion of WBMRI in pediatric patients, exploring protocols and other technical considerations, clinical indications, implementation challenges and troubleshooting, as well as controversies in widespread adoption, while considering emerging trends and directions. Commonalities and variations in WBMRI protocols across indications and institutions are presented, highlighting the need for greater standardization. Barriers to WBMRI access, particularly in resource-limited settings, are considered, along with potential solutions. The available evidence regarding potential patient benefit from WBMRI across various applications is summarized.

Osteoarticular tuberculosis: imaging findings in pediatric patients

Osteoarticular tuberculosis (TB) is an uncommon form of extrapulmonary TB that has the potential to damage joints and bones, generating long-term impairment. Mainly, the initial diagnosis of osteoarticular TB relies on clinical findings and imaging. When required, imaging can aim for less invasive tissue or fluid sampling for pathology, microbiology, and molecular biology analysis. Most TB diagnosis tests have variable and frequently poor sensitivities; however, bone biopsy samples have demonstrated a high percentage of culture positivity. Clinical and imaging findings of osteoarticular TB often mimic other processes, such as rheumatoid arthritis or chronic recurrent multifocal osteomyelitis. When the infection affects the growth plates, angular deformities and extremity length discrepancies can arise. Unfortunately, several osteoarticular TB cases are detected late due to the nonspecific nature of clinical symptoms and non-characteristic imaging findings. This article reviews the most common and atypical osteoarticular TB imaging presentations to increase awareness of osteoarticular TB.

Chronic Noninfectious Osteomyelitis: A Review of Imaging Findings

Chronic noninfectious osteomyelitis or chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is an autoinflammatory bone disorder primarily affecting the pediatric age group. Currently, it is diagnosed on the basis of clinical, laboratory, and imaging features. Imaging plays a crucial role in the diagnosis and follow-up of CNO with whole body magnetic resonance imaging (WBMRI) being the main modality. Radiographs assist in exclusion of common differential diagnoses like infections and malignancy. WBMRI aids in disease detection and exclusion of differential diagnoses, identifies additional lesions, and has a role in ascertaining the pattern of bony involvement which helps with prognostication and grading. Recent recognition of specific morphological and distribution patterns on WBMRI is increasingly allowing an upfront diagnosis of this entity to be made on imaging alone. It is also helpful for assessment of response to therapy during follow-up. This review aims to summarize the role of imaging in the evaluation of CNO, with special emphasis on WBMRI in its assessment.

An improved understanding of pediatric chronic nonbacterial osteomyelitis pathophysiology informs current and future treatment

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease that primarily affects children and young people. It can cause significant pain, reduced function, bone swelling, and even (vertebral body) fractures. Because of a limited understanding of its pathophysiology, the treatment of CNO remains empiric and is based on relatively small case series, expert opinion, and personal experience. Several studies have linked pathological NOD-kike receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome activation and the resulting imbalance between pro- and anti-inflammatory cytokine expression with CNO. This agrees with elevated pro-inflammatory (mostly) monocyte-derived protein signatures in the blood of CNO patients that may be used as future diagnostic and/or prognostic biomarkers. Recently, rare variants in the P2RX7 gene, encoding for an ATP-dependent transmembrane channel, were linked with increased NLRP3 inflammasome assembly and prolonged monocyte/macrophage survival in CNO. Although the exact molecular mechanisms remain unclear, this will inform future target-directed and individualized treatment. This manuscript reviews most recent developments and their impact on diagnostic and therapeutic strategies in CNO.

Chronic Recurrent Multifocal Osteomyelitis Involving the Spine, Sternum, and Lower Extremities: A Case Report

Chronic recurrent multifocal osteomyelitis (CRMO) or chronic nonbacterial osteitis is a sterile autoinflammatory disease of bone in children that can mimic infectious osteomyelitis and osteosarcoma. Early diagnosis, treatment, and long-term follow-up of CRMO are essential. We describe a 10-year-old boy who presented with 15 days of left ankle bone more than joint pain, swelling, and limp. Plain radiographs and magnetic resonance imaging scans were nondiagnostic of osteomyelitis and tibial irrigation and biopsy were negative for infection and malignancy. Four years later, he again presented with similar pain in his right ankle. Repeat bone biopsy noted reactive bone changes and bone culture was sterile. Whole-body magnetic resonance imaging revealed multiple enhancing lesions in the long bones of bilateral lower extremities, spine, and sternum. He was diagnosed with CRMO, and treatment with celecoxib and subsequently pamidronate, infliximab, and methotrexate were initiated. After 6 months of treatment, the patient's gait and pain improved, and 2 years later, his CRMO was in clinical and radiologic remission. Of note, he developed palmoplantar pustular psoriasis, commonly seen in CRMO, that was not determined to be from tumor necrosis factor inhibition.

Bacterial osteomyelitis in pediatric patients: a comprehensive review

Bacterial osteomyelitis, an inflammatory response in the bone caused by microorganisms, typically affects the metaphysis in the skeletally immature. Bacterial osteomyelitis possesses a significant diagnostic challenge in pediatric patients due to its nonspecific clinical presentation. Because the metaphysis is the primary focus of infection in skeletally immature patients, understanding the normal physiologic, maturation process of bones throughout childhood allows to understand the pathophysiology of osteomyelitis. Timely and accurate diagnosis is crucial to initiate appropriate treatment, and prevent long-term sequelae and efforts must be made to isolate the causative organism. The potential causative organism changes according to the age of the patient and underlying medical conditions. Staphylococcus Aureus is the most common isolated bacteria in pediatric pyogenic osteomyelitis whereas Kingella Kingae is the most common causative agent in children aged 6 months to 4 years. Imaging plays a pivotal role in the diagnosis, characterization, evaluation of complications, and follow up of bacterial osteomyelitis. Imaging also plays a pivotal role in the evaluation of potential neoplastic and non-neoplastic mimickers of osteomyelitis. In children, MRI is currently the gold standard imaging modality when suspecting bacterial osteomyelitis, whereas surgical intervention may be required in order to isolate the microorganism, treat complications, and exclude mimickers.

Spine Involvement and Vertebral Deformity in Patients Diagnosed with Chronic Recurrent Multifocal Osteomyelitis

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory disorder of bone, typically arising adjacent to the physes of long bones but also seen throughout the skeleton. For patients with spinal involvement, CRMO lesions can cause compression deformities with a range of severity from minimal anterior wedging to circumferential height loss, known as vertebra plana. This study examines a large cohort of CRMO patients to determine the prevalence of spine involvement and vertebral deformity.

METHODS

This is a retrospective review of all patients with a diagnosis of CRMO seen at our institution between January 2003 and December 2020. These patients were identified through a prospectively maintained database of all CRMO patients seen at the institution. A retrospective review was undertaken to identify all patients with spinal involvement and determine the prevalence of CRMO in the spine and its effects on vertebral height and deformity.

RESULTS

Of 170 patients included in this study, 48 (28.2%) were found to have spinal involvement. Among patients with spinal involvement, vertebral body lesions were identified in 27 (56.3%) patients. The remaining lesions were in the sacrum or posterior elements. Radiographic evidence of the vertebral body height loss was noted in 23 of these 27 patients.

CONCLUSIONS

This cohort of CRMO patients demonstrates that 28% of patients have spinal involvement, and 48% of those patients have vertebral body height loss. While the ideal treatment for spinal CRMO has yet to be determined, imaging studies, including whole-body MRI and spine-specific MRI, are useful in identifying vertebral lesions and deformities. Identification and surveillance of these lesions are important as the disorder has a relapsing and remitting course, and patients can develop significant vertebral body height loss. Once deformity has developed, we have seen no evidence of reconstitution of the height of the collapsed vertebra. Bisphosphonates have been successful in preventing the progression of vertebral body height loss.

LEVEL OF EVIDENCE

Level II: Retrospective study investigating spinal involvement and prevalence of vertebral body deformity in patients diagnosed with CRMO.

A Case of Chronic Recurrent Multifocal Osteomyelitis (CRMO)

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare but underdiagnosed, severe inflammatory bone disease that primarily affects children. It's typically characterized by bone pain, especially within the metaphysis of long bones, clavicles, and vertebrae, but it can present in any bone and with varied presentation, including extraosseous symptoms that may be associated with other autoimmune/inflammatory diseases. Chronic recurrent multifocal osteomyelitis is a sterile bone disease that does not typically have an infectious source. Its pathogenesis involves the dysregulation of the innate immune system via upregulation of cytokines, inflammasomes, and osteoclastic properties. Diagnostic testing is nonspecific and includes X-ray and MRI, bone biopsy, inflammatory markers, and autoimmune markers. Chronic recurrent multifocal osteomyelitis is established by the diagnosis of exclusion. First-line treatment is nonsteroidal anti-inflammatory drugs (NSAIDs); if vertebral involvement is present, a bisphosphonate is typically added. This case report emphasizes the importance of considering CRMO as a differential diagnosis of multifocal bone pain in children.

MRI of Pediatric Foot and Ankle Conditions

The increase in competitive sports practice among children and lack of ionizing radiation have resulted in a higher demand for MRI examinations. MRI of the children skeleton has some particularities that can lead orthopedists, pediatricians, and radiologists to diagnostic errors. The foot and ankle have several bones with abundant radiolucent and high signal intensity cartilage in several ossification centers, apophysis and physis, that can make this interpretation even harder. The present revision aims to show, how to differentiate between normal developmental findings and anatomic variants from pathologic conditions, whether mechanical, inflammatory, infectious, or neoplastic.

Primary chronic osteomyelitis of the jaw - a descriptive study of the condition and its occurrence in Sweden between 2012 and 2018

PURPOSE

Primary chronic osteomyelitis (PCO) of the jaw is a non-infectious, inflammatory state of the jawbone of unknown etiology.  This study aimed to investigate the occurrence of PCO in Sweden between the years 2012 and 2018, the characteristics of the condition, treatment methods, and outcomes.  Material and methods: The search for patients with PCO in Sweden 2012-2018 was performed at 24 oral and maxillofacial surgery units in Sweden.

RESULTS

During this 6-year period, 17 patients were identified as diagnosed with PCO in Sweden. The mean age was 10.6 years at diagnosis, and the female:male ratio was 4:1.

CONCLUSION

We conclude that PCO is a very rare disease in Sweden, and that standardized, well-defined criteria are necessary to calculate incidence rates but also to increase knowledge about etiology, clinical characteristics, and treatment outcomes in rare conditions such as PCO.

Bone marrow edema in children: chronic nonbacterial osteomyelitis and its mimickers

Bone marrow is a highly cellular tissue undergoing significant developmental and physiologic changes with age. Indeed, with maturation from pediatric to the adult age there is a progressive, centrifugal conversion from red to yellow bone marrow. Histological characteristics of bone marrow are reflected in MR image signal. MR is therefore extremely sensitive in detecting pathological changes which are mostly characterized by increased free water causing high signal intensity on T2. Among the numerous diseases causing bone marrow edema in children chronic nonbacterial osteomyelitis (CNO) certainly has to be mentioned. This idiopathic inflammatory disorder is characterized by nonspecific migrating symptoms like skeletal pain with phases of exacerbations and relapses with alternating acute and chronic MR signs and it is often a diagnosis of exclusion. Hence, with bone marrow edema, various features at imaging should be considered to differentiate malignancies such as osseous lymphoma, osteosarcoma, and Ewing's sarcoma as well as benign lesions like osteomyelitis, post-traumatic, or post-treatment bone marrow edema. The aim of this review is to recall the main characteristics of CNO and provide an overview of its main mimickers highlighting similarities and differences.

Imaging approach to pediatric calvarial bulges

Palpable calvarial lesions in children may require multi-modality imaging for adequate characterization due to non-specific clinical features. Causative lesions range from benign incidental lesions to highly aggressive pathologies. While tissue sampling may be required for some lesions, others have a typical imaging appearance, and an informed imaging approach facilitates diagnosis. This review illustrates imaging findings of common and clinically important focal pediatric calvarial bulges to aid the radiologist in narrowing the differential diagnosis and directing appropriate referral. We focus on birth-related lesions, congenital abnormalities, and modeling disturbances (i.e., those that produce a change in calvarial contour early in development), normal variants, and neoplastic lesions with their mimics.

Chronic recurrent multifocal osteomyelitis: Case report and review of the literature

BACKGROUNDS

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory disease.

OBJECTIVE

This report aims to analyze the clinical characteristics of CRMO and enhance clinicians' comprehension. We present 3 atypical cases, highlighting their unique clinical features, diagnostic challenges, and effective treatment strategies.

METHODS

We retrieved 3 CRMO cases in our hospital from September 2019 to August 2022. The clinical features were analyzed retrospectively, and relevant literatures were reviewed.

RESULTS

All 3 cases initially presented with bone pain, normal leucocyte counts, negative rheumatoid factors and no signs of sclerotic or hyperostotic lesions. Case 1, a 12-year-old girl, exhibited concurrent acne on the forehead and historic necrotizing lymphadenitis, a previously unreported association with CRMO. Case 2, a 14-year-old boy, tested positive for human leukocyte antigen-B27 and displayed scoliosis along with multifocal osteomyelitis. Case 3, a 9-year-old girl, presented with scoliosis, and chest computed tomography revealed changes in the T8 vertebral body, initially suggesting Langerhans cell histiocytosis. Bone biopsy was conducted in case 1 and case 3, revealing chronic inflammation. All 3 cases affected long bones, pelvis, and vertebra, involving 8, 6 and 5 bones, respectively, identified by magnetic resonance imaging. Genetic analysis was undertaken in cases 1 and 2 but no pathogenic mutations were identified. Upon the confirmation of a CRMO diagnosis, all patients were initiated on a treatment regimen comprising nonsteroidal anti-inflammatory drugs and tumor necrosis factor-α inhibitors. In cases 1 and 2, due to the severity of their bone pain, they were also administered to disease-modifying anti-rheumatic drugs, specifically methotrexate. All 3 patients achieved remission of bone pain. To gain a more comprehensive understanding of CRMO, we conducted a thorough review of relevant literature.

CONCLUSION

CRMO is a rare autoinflammatory bone disorder with diverse clinical presentations and a lack of specific laboratory tests, which leads to potency to misdiagnosis or delayed diagnosis. By raising awareness and improving diagnostic criteria, physicians are now better equipped to identify CRMO. We contribute to share our understanding of CRMO by presenting 3 cases with untypical clinical features, highlighting the importance of recognizing this rare condition for timely and effective management.

Pictorial review: challenges in distinguishing bilateral metaphyseal marrow abnormalities on magnetic resonance imaging

The paediatric metaphysis is afflicted by a wide range of pathological processes as it is the most metabolically active and well-vascularised part of the developing skeleton. This review focuses on metaphyseal marrow signal change detected with magnetic resonance imaging, which is most often occult on radiographs. When bilateral, these imaging appearances frequently present a diagnostic quandary. This review assists the radiologist to confidently dismiss physiological signal change and confidently work through the differential diagnosis. This is achieved by illustrating a practical method of classifying signal change into four categories: physiological red marrow, red marrow reconversion, marrow infiltration, and oedema-like marrow signal intensity. In doing so, various pathological entities are reviewed along with imaging pearls and next-step investigations.

Chronic non-bacterial osteomyelitis (CNO) in childhood and adolescence - a disease with many faces

BACKGROUND

Chronic non-bacterial osteomyelitis (CNO) is a chronic inflammatory skeletal disease that affects particularly children and adolescents and is often diagnosed with a delay. With whole-body MRI, early diagnosis of this disease is possible in many cases. Since children and adolescents frequently present with non-specific complaints for outpatient radiological diagnosis, every radiologist should have basic knowledge of this complex clinical picture.

MATERIALS

In this review the basics and current findings regarding the disease are discussed. Unusual courses are also presented.

RESULTS AND CONCLUSION

With knowledge of the radiographic and MR tomographic characteristics of the mostly multifocal bone lesions, the diagnosis of CNO can be reliably made in many cases. In particular, the early use of whole-body MRI plays an important role. Thus, therapeutic delays and resulting complications and the number of unnecessary biopsies for diagnosis can be reduced.

Pediatric mandibular chronic nonbacterial osteomyelitis: A case report with 12 years of radiologic follow-up

Chronic nonbacterial osteomyelitis (CNO) is histologically characterized by nonspecific osteitis. This inflammatory disorder, which lacks an infectious origin, typically presents with chronic pain and swelling at the affected site that can persist for months or even years. However, it is rare for CNO to affect the mandible. A 10-year-old girl presented with a primary complaint of pain in her left mandible. She had no significant medical or dental history. On examination, swelling was visible on the left buccal side, and imaging revealed radiolucent bone deterioration within the left mandible. This case report presents the radiological changes observed over a 12-year follow-up period. Variations in radiopacity, radiolucency, and periosteal reactions were noted periodically. This case highlights the radiological characteristics and findings that are crucial for the diagnosis of CNO, a condition for which no clear diagnostic criteria are currently available.

A clinico-radiological review of chronic non-bacterial osteomyelitis in paediatrics, adolescents, and adults: demystifying a forgotten differential

Chronic non-bacterial osteomyelitis (CNO), also known as non-bacterial osteitis, is a chronic autoinflammatory disease of unknown aetiology that primarily occurs in the paediatric population, although rare cases of adult-onset disease also exist. CNO has non-specific clinical and radiological presentations, and the affected population often present with bone pain of insidious onset secondary to sterile bony inflammation that can be associated with swelling, focal tenderness, and warmth at the affected sites. The pattern of bony involvement appears to be dependent on the age of onset, with adults frequently having axial skeletal lesions and children and adolescents often being affected in the appendicular skeletal sites. CNO is a diagnosis of exclusion, and imaging is heavily relied on to identify and characterise the bony lesions in addition to exclude diseases that can mimic CNO. Magnetic resonance imaging is often the reference standard with biochemical and histopathological findings being complementary. Although combining imaging methods can be used to facilitate the diagnosis, a single technique could be adequate depending on the clinical picture. Given the relatively rare incidence of CNO, limited awareness of the disease among care providers, and its similarity in clinical and radiological presentation to various bony diseases, there are often long delays in diagnosis, with adults being unfavourably affected compared to paediatrics and adolescents. This review of CNO will describe the condition, overview its clinical presentation, highlight the radiological features, and emphasise clinical pearls that can aid in diagnosis and ruling out the mimics.

Clinical Characteristics of Pediatric Clavicular Lesions: A Retrospective Analysis of 20 Cases

Background This research aims to study the diagnostic patterns, anatomical locations, and age-related trends in pediatric clavicular lesions, filling a gap in pediatric-specific data for these conditions. Methodology A retrospective study of 20 pediatric patients (aged ≤14 years) with clavicular lesions was conducted based on inclusion and exclusion criteria emphasizing confirmed diagnosis and treatment specifics. The diagnostic process relied on open biopsy, followed by excision or curettage and histopathological examination. Results The study primarily involved patients with an average age of 7.1 ± 3.8 years. Eosinophilic granuloma was the most common diagnosis (30% of cases), particularly in the age group of 0-3 years. Clavicular lesions predominantly manifested as either a palpable lump or localized swelling with pain. The medial of the clavicle was the most frequent lesion location. No malignant tumors were found, and the functional outcomes post-treatment were satisfactory. Conclusions Pediatric clavicular lesions exhibit distinct diagnostic and anatomical characteristics compared to adults. Eosinophilic granuloma is significantly prevalent in early childhood, necessitating age-specific diagnostic and therapeutic approaches. The study advocates for multidisciplinary collaboration in the treatment and improved understanding of these lesions, which are vital for pediatric orthopedic oncology.

Pediatric Ribs at Chest Radiography: Normal Variants and Abnormalities

Normal variants and abnormalities of the ribs are frequently encountered on chest radiographs. Accurate identification of normal variants is crucial to avoid unnecessary investigations. A meticulous evaluation of rib abnormalities can provide valuable insights into the patient's symptoms, and even when no osseous condition is suspected, rib abnormalities may offer critical clues to underlying conditions. Rib abnormalities are associated with various conditions, including benign tumors, malignant tumors, infectious and inflammatory conditions, vascular abnormalities, metabolic disorders, nonaccidental injuries, malformation syndromes, and bone dysplasias. Abnormalities of the ribs are classified into three groups based on their radiographic patterns: focal, multifocal, and diffuse changes. Focal lesions are further subdivided into nonaggressive lesions, aggressive lesions, and infectious and inflammatory disorders. Radiologists should be aware of individual disorders of the pediatric ribs, including their imaging findings, relevant clinical information, and underlying pathogenesis. Differential diagnoses are addressed as appropriate. Since chest radiographs can suffice for diagnosis in certain cases, the authors emphasize a pattern recognition approach to radiographic interpretation. However, additional cross-sectional imaging may be necessary for focal lesions such as tumors or inflammatory conditions. Awareness of disease-specific imaging findings helps ascertain the nature of the lesion and directs appropriate management. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging findings of juvenile idiopathic arthritis and autoinflammatory diseases in children

Juvenile idiopathic arthritis (JIA) is a collective term for pediatric inflammatory arthritis of unknown etiology, which presents diverse clinical and imaging findings. The pathogenesis is complex; however, most cases stem from an autoimmune mechanism. Herein we provide a short review of imaging findings of JIA. Imaging assessment begins with plain radiography demonstrating joint swelling, periarticular osteopenia, and juxtaarticular bone erosion. Bone erosion occurs later in JIA. Instead, aberrant epimetaphyseal growth often gives the first clue to the diagnosis. US and MRI can demonstrate the details of the synovium, cartilage, and subchondral bone. JIA is subdivided into oligoarthritis, polyarthritis (rheumatoid factor-negative and positive), psoriatic arthritis, enthesitis-related arthritis, and systemic JIA. Awareness of the different clinical characteristics, pathogenic background, and prognosis of each subtype facilitates a more advanced, imaging-based diagnosis. Unlike the other types, systemic JIA is an autoinflammatory disease accompanied by inflammatory cytokinemia and systemic symptoms stemming from aberrant activation of the innate immunity. Other autoinflammatory diseases, both monogenic (e.g., NOMID/CINCA) and multifactorial (e.g., CRMO), are also discussed.

MRI of Pediatric Foot and Ankle Conditions

The increase in competitive sports practice among children and lack of ionizing radiation have resulted in a higher demand for MRI examinations. MRI of the children skeleton has some particularities that can lead orthopedists, pediatricians, and radiologists to diagnostic errors. The foot and ankle have several bones with abundant radiolucent and high signal intensity cartilage in several ossification centers, apophysis and physis, that can make this interpretation even harder. The present revision aims to show, how to differentiate between normal developmental findings and anatomic variants from pathologic conditions, whether mechanical, inflammatory, infectious, or neoplastic.

MRI features of spinal chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis in children

BACKGROUND

Spinal lesions in pediatric chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis (CRMO/CNO) can cause permanent sequelae; thus, early recognition of these is vital for management.

OBJECTIVE

To characterize the MR imaging features and patterns of pediatric spinal CRMO/CNO.

MATERIALS AND METHODS

This cross-section study received IRB approval. The first available MRI with documented spine involvement in children with CRMO/CNO was reviewed by a pediatric radiologist. Descriptive statistics were used to describe the characteristics of vertebral lesions, disc involvement, and soft tissue abnormality.

RESULTS

Forty-two patients were included (F:M, 30:12); median age was 10 years (range 4-17). At diagnosis, 34/42 (81%) had spine involvement. Kyphosis in 9/42 (21%) and scoliosis in 4/42 (9.5%) patients were present at the time of spinal disease recognition. Vertebral involvement was multifocal in 25/42 (59.5%). Disc involvement was found in 11/42 (26%) patients, commonly in the thoracic spine and often with adjacent vertebrae height loss. Posterior element abnormalities were present in 18/42 patients (43%) and soft tissue involvement in 7/42 (17%). One hundred nineteen vertebrae were affected, commonly the thoracic vertebrae (69/119; 58%). Vertebral body edema was focal in 77/119 (65%) and frequently superior (42/77; 54%). Sclerosis and endplate abnormality were present in 15/119 (13%) and 31/119 (26%) vertebrae, respectively. Height loss was present in 41/119 (34%).

CONCLUSION

Chronic non-bacterial osteomyelitis of spine is usually thoracic. Vertebral body edema is often focal at the superior vertebral body. Kyphosis and scoliosis occur in a quarter and vertebral height loss in a third of children at spinal disease recognition.

Pediatric-onset limited ANCA-associated vasculitis arising during pre-existing chronic recurrent multifocal osteomyelitis

BACKGROUND

Granulomatosis with polyangiitis (GPA) is an autoimmune disease characterized by chronic vasculitis involving small to medium sized arteries, granulomatous inflammation of the upper and lower respiratory tracts, pauci-immune necrotizing glomerulonephritis, as well as vasculitis of other organs. Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory syndrome characterized by sterile bone inflammation.

CASE PRESENTATION

We report a case of CRMO that was doing well on non-steroidal anti-inflammatory drugs (NSAID for 6 years and then developed ANCA positive limited GPA presenting with pyoderma gangrenosum, persistent bilateral otalgia with serous otitis, otorrhea, then sensorineural hearing loss.

CONCLUSION

This is the first report of limited GPA initially presenting as pyoderma gangrenosum in a patient with underlying CRMO. It is unclear how the pathology of an autoimmune and an autoinflammatory condition can overlap.

Classification and management strategies for paediatric chronic nonbacterial osteomyelitis and chronic recurrent multifocal osteomyelitis

INTRODUCTION

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disease that most commonly affects children and adolescents causing significant pain and damage to bones. The absence of diagnostic criteria and biomarkers, an incomplete understanding of the molecular pathophysiology, and lack of evidence from randomized and controlled trials make the diagnosis and care challenging.

AREAS COVERED

This review provides an overview of the clinical and epidemiological features of CNO and displays diagnostic challenges and how they can be addressed following strategies used internationally and by the authors. It summarizes the molecular pathophysiology, including pathological activation of the NLRP3 inflammasome and IL-1 secretion, and how these observations can inform future treatment strategies. Finally, it provides a summary of ongoing initiatives aiming at classification criteria (ACR/EULAR) and outcome measures (OMERACT) that will enable the generation of evidence through clinical trials.

EXPERT OPINION

Scientific efforts have linked molecular mechanisms to cytokine dysregulation in CNO, thereby delivering arguments for cytokine blocking strategies. Recent and ongoing collaborative international efforts are providing the basis to move toward clinical trials and target directed treatments for CNO that find approval by regulatory agencies.

Diagnosis and Treatment of Chronic Non-bacterial Osteomyelitis: A Survey on Current Practices Adopted by Pediatric Rheumatologists in Saudi Arabia

INTRODUCTION

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease usually managed by pediatric rheumatologists (PRs). There is a need for a consensus treatment plan to minimize the diversity in clinical practice in the diagnosis and management of CNO. In this study, we explored the practice of PRs in Saudi Arabia on the diagnosis and treatment of patients with CNO.

METHODS

This is a cross-sectional study that was conducted among PRs in Saudi Arabia (May to September 2020). A survey was performed among PRs registered in the Saudi Commission for Health Specialties using an electronic-based questionnaire. The survey consisted of 35 closed-ended questions about the diagnosis and management of CNO patients. We explored the approaches adopted by PRs in diagnosing and monitoring the disease activity, their awareness of clinical possibilities that necessitate ordering bone biopsy, and the treatment choices they considered for CNO patients.

RESULTS

We scrutinized data from a total of 77% (n=41/53) PRs who responded to our survey. Magnetic resonance imaging (MRI) was reported as the most frequently used modality in suspected CNO (82%, n=27/33), followed by plain X-ray (61%) and bone scintigraphy (58%). Magnetic resonance imaging of a symptomatic site is the imaging modality of choice for the diagnosis of CNO (82%), Followed by X-ray (61%) and bone scintigraphy (58%). The reasons for performing bone biopsy were unifocal lesions (82%), unusual sites of presentation (79%), and multifocal lesions (30%). The preferred treatment regimens were bisphosphonates (53%), non-steroidal anti-inflammatory drugs alone (43%), or biologics with bisphosphonates (28%). The reasons to upgrade the treatment in CNO included the development of vertebral lesions (91%), the development of new lesions in MRI (73%), and the elevation of inflammatory markers (55%). The disease activity was assessed by history and physical examination (91%), inflammatory markers (84%), MRI of targeted symptomatic site (66%), and a whole-body MRI (41%).

CONCLUSIONS

The approach to diagnosis and treatment of CNO varies among PRs in Saudi Arabia. Our findings provide a background for the development of a consensus treatment plan for challenging CNO patients.

How Have the Diagnosis and Treatment of Chronic Recurrent Multifocal Osteomyelitis Changed Over Time?

PURPOSE

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory condition characterized by sterile bone lesions. There appears to be a shift in the diagnostic modalities and treatment over the past decades despite insufficient published data. The purpose of this study was to document: 1) the number of patients diagnosed with CRMO, 2) patient demographics, 3) disease characteristics at presentation, 4) diagnostic modalities employed, and 5) treatments prescribed at our institution over a 30-year period.

METHODS

This single-center, retrospective cohort study included children diagnosed with CRMO who presented between 1990 and 2020. The electronic medical records were queried using numerous search terms. Patients were excluded if CRMO was included in the differential diagnosis but was not confirmed at the time of chart review or if CRMO was suspected early in the disease course but the patient was ultimately diagnosed with another condition. The predictor (time in years) and outcome variables (diagnostic modalities and treatment types) were tested using bivariate analyses using IBM SPSS, Version 27 (IBM Corp., Armonk, NY).

RESULTS

A total of 224 patients were diagnosed with CRMO during the observation period (68.3% female; 67.4% white). The number of patients diagnosed over the past decade rose by 215%, as compared to the previous 2 decades (1990 to 2010). Regional magnetic resonance imaging (83.8%) and biopsy (66.5%) were the most utilized diagnostic modalities over the past decade, with a statistically significant decline in the proportion of biopsies performed (66.5% during the past decade vs 84.9% in the previous 2 decades, P = .01). Over the past decade, nonsteroidal anti-inflammatory drugs (40.1%), disease-modifying antirheumatic drugs (27.1%), and tumor necrosis factor inhibitors (21.1%) were the most commonly used treatments, with a statistically disproportionate increase in the use of tumor necrosis factor inhibitors (21.1% during the past decade vs 3.8% in the previous 2 decades, P < .001).

CONCLUSIONS

This is one of the largest CRMO cohort studies and the only study to observe changes in diagnostic modalities and treatment over a 30-year period. Future studies should assess the impact of variations in clinical presentation, time to diagnosis, diagnostic modalities, and management as predictors of disease outcomes.

Nonbacterial and bacterial osteomyelitis in children: a case-control retrospective study

Purpose

Osteomyelitis is a group of bone infectious (bacterial osteomyeilitis-BO) and noninfectious inflammatory diseases (nonbacterial osteomyelitis-NBO) with similar clinical, radiology, and laboratory features. Many patients with NBO are misdiagnosed as BO and receive unnecessary antibiotics and surgery. Our study aimed to compare clinical and laboratory features of NBO and BO in children, to define key discriminative criteria, and to create an NBO diagnostic score (NBODS).

Methods

The retrospective multicenter cohort study included clinical, laboratory, and instrumental information about histologically confirmed NBO (n = 91) and BO (n = 31). The variables allowed us to differentiate both conditions used to construct and validate the NBO DS.

Results

The main differences between NBO and BO are as follows: onset age-7.3 (2.5; 10.6) vs. 10.5 (6.5; 12.7) years (p = 0.03), frequency of fever (34.1% vs. 90.6%, p = 0.0000001), symptomatic arthritis (67% vs. 28.1%, p = 0.0001), monofocal involvement (28.6% vs. 100%, p = 0.0000001), spine (32% vs. 6%, p = 0.004), femur (41% vs. 13%, p = 0.004), foot bones (40% vs. 13%, p = 0.005), clavicula (11% vs. 0%, p = 0.05), and sternum (11% vs. 0%, p = 0.039) involvement. The following four criteria are included in the NBO DS: CRP ≤ 55 mg/l (56 points), multifocal involvement (27 points), femur involvement (17 points), and neutrophil bands ≤ 220 cell/μl (15 points). The sum > 17 points allowed to differentiate NBO from BO with a sensitivity of 89.0% and a specificity of 96.9%.

Conclusion

The diagnostic criteria may help discriminate NBO and BO and avoid excessive antibacterial treatment and surgery.

Whole-body MRI at initial presentation of pediatric chronic recurrent multifocal osteomyelitis and correlation with clinical assessment

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a diagnosis of exclusion, relying heavily on whole-body magnetic resonance imaging (WB-MRI) for diagnosing and evaluating response to therapy. Information with respect to disease distribution and imaging correlation with clinical disease severity at initial presentation is lacking.

OBJECTIVE

To retrospectively characterize distribution of disease on WB-MRI and to correlate imaging findings with disease severity at initial rheumatology presentation.

MATERIALS AND METHODS

Using a modified version of a recently devised imaging-based scoring system, we evaluated disease distribution and correlation between findings on WB-MRI and clinical disease severity in 54 patients presenting for initial evaluation of CRMO. Symptomatic lesion sites were extracted from chart review and physician global assessment was determined by the consensus of two rheumatologists.

RESULTS

Sites of CRMO involvement evident on imaging at initial presentation had a strong predilection for the pelvis and lower extremities. There was significant correlation between the number of lesions detected on WB-MRI and total clinical severity score at initial rheumatology presentation (P&lt;0.01). However, no other imaging parameter correlated with disease severity.

CONCLUSION

While the overall number of lesions identified on MRI correlates with clinical severity scores at initial imaging, other MR parameters of CRMO lesions may not be reliable indicators of disease severity at initial presentation. Further research is needed to assess whether these parameters are implicated in longitudinal disease severity or overall response to therapy.

Non-neoplastic pathologies mimicking sarcoma - Experience from a tertiary referral centre multidisciplinary team

OBJECTIVE

Distinguishing non-neoplastic tumour-mimicking pathologies from bone and soft tissue tumours is one of the fundamental aims of a tertiary centre sarcoma multidisciplinary team (MDT) service. In this study, we aim to analyse the incidence of non-neoplastic lesions referred to a tertiary referral service as suspected sarcoma, and to analyse the spectrum of conditions comprising these tumour-mimicking pathologies.

MATERIALS AND METHODS

We conducted a retrospective observational study compiling the biopsy-proven non-neoplastic outcomes of suspected sarcoma cases referred to our MDT in the last year. We identified all referrals made to our service between 1st January 2020 and 31st December 2020 and compiled their histological diagnoses.

RESULTS

A total of 976 new cases were referred to our MDT as suspected sarcoma in one year. Of these referrals, 8.6% (84/976) received a biopsy-proven outcome of non-neoplastic pathology. These non-neoplastic outcomes were categorised into the following types of pathology: 32.1% vascular, 31.0% inflammatory, 14.3% traumatic, 6.0% degenerative, 6.0% idiopathic, 4.8% infective, 3.6% metabolic, 1.2% autoimmune, and 1.2% genetic.

CONCLUSION

A significant proportion of pathologies referred to a tertiary centre sarcoma MDT are non-neoplastic in nature. These lesions are made up of a range of pathologies, with vascular and inflammatory conditions being the most common. Our study, the first of its kind, offers clinicians an insight into tumour-mimicking pathologies encountered by a tertiary centre.

Chronic nonbacterial osteomyelitis: the role of whole-body MRI

Background

Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is a noninfectious autoinflammatory disorder that occurs primarily in children and adolescents and is characterized by episodic musculoskeletal pain with a protracted course.

Main body

Traditionally, the diagnosis of CNO is made by exclusion and commonly requires bone biopsy to rule out infection and malignancy. However, bone biopsy may be avoided when imaging and clinical characteristic features are present, such as multifocal bone lesions at typical sites, no constitutional symptoms and no signs of infection in laboratory test results. Whole-body magnetic resonance imaging (WB-MRI) can assess signs of acute and chronic inflammation and enables the detection of CNO typical patterns of lesion location and distribution, thereby helping to exclude differential diagnosis. The goal of the present study paper is to review the main clinical and imaging aspects of the disease with emphasis on the role of WB-MRI in the diagnosis, assessment of disease burden and follow-up monitoring.

Conclusion

Radiologists need to be familiar with the imaging features to suggest the diagnosis as the early therapy may help to avoid irreversible secondary damage of skeletal system.

Not all benign: disease course, complications, and sequalae of chronic recurrent multifocal osteomyelitis in children

PURPOSE OF REVIEW

Advances in pathogenesis of chronic recurrent multifocal osteomyelitis in children (CRMO) have shaped therapeutic strategies. The use of whole-body MRI (WBMRI) and improved awareness of CRMO has increased rates and timeliness of CRMO diagnoses. In this review, we highlight the findings from recently published CRMO cohorts and describe the course, complications, and long-term sequalae of CRMO. It is important for clinicians to be aware of the potential for long-term sequelae in order to optimize therapy and avoid complications.

RECENT FINDINGS

Despite recent advances in defining disease pathogenesis, children with CRMO continue to suffer from complications and deformities. Involvement of the spine can be asymptomatic and is not as rare as previously suggested. This can result in damaging outcomes, such as vertebral fractures and permanent deformities. A subset of patients has polycyclic disease course and some continue to have active disease for years and well into adulthood, with significant impacts on quality of life.

SUMMARY

These recent findings have considerable implication on clinical practice regarding diagnosis, treatment, and monitoring of the disease. Collectively, they support the need for continued monitoring of the disease and screening using comprehensive imaging, such as WBMRI.

Chronic recurrent multifocal osteomyelitis, a rare disease. Case report

Introduction: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory bone disease usually observed in children and adolescents. It is caused by an imbalance between proinflammatory and anti-inflammatory factors. To establish its diagnosis, it is necessary to integrate clinical and laboratory elements that are typically aimed at ruling out other conditions, constituting a diagnosis of exclusion. Treatment is based on non-steroidal anti-inflammatory drugs and other drugs in specific cases. Case presentation: A 16-year-old female patient with a 1-year history of joint pain, especially in the knees, accompanied by signs of local inflammation was admitted to the emergency department of a quaternary care hospital due to a fever >38.5°, odynophagia, asthenia, and adynamia over the last two days. The patient underwent multiple extension studies, including laboratory, imaging and histopathological tests, which ruled out various etiologic causes. She received empirical antibiotic treatment without remission of symptoms, so a diagnosis of CRMO was finally established and outpatient treatment with non-steroidal anti-inflammatory drugs and corticosteroids was indicated, obtaining a favorable response. Conclusions: CRMO should be considered in children and adolescents with bone pain and a poorly defined clinical history with non-specific laboratory, imaging and histopathological findings. To date, little is known about CRMO, so it is necessary to carry out research and expand the knowledge related to this disease.

A Case of Sterile Osteomyelitis: Chronic Recurrent Multifocal Osteomyelitis (CRMO)

Chronic recurrent multifocal osteomyelitis (CRMO) is a rarely reported autoimmune inflammatory condition affecting children and young adults. The typical complaint is recurrent severe bone pain at multiple sites; often imaging suggests features of osteomyelitis or malignancy. However, the biopsy is always negative for any growth in culture and histopathology detects only inflammatory cells. This is a diagnosis of exclusion with various diagnostic criteria. We had a 20-year-old male presenting with recurring pain and swelling in the right hand and left foot for more than seven months. Imaging revealed bone marrow edema with the expansion of bone and sclerosis involving the third metacarpal of the right hand and first metatarsal of the left foot. Acute phase reactants were mildly raised with biopsy showing inflammatory cells. However, the cultures grown from the lesion were sterile. After comparing it with the various diagnostic criteria, a diagnosis of CRMO was made.

Chronic nonbacterial osteomyelitis in children: a multicentre Belgian cohort of 30 children

BACKGROUND

To evaluate clinical characteristics, imaging findings, therapeutic approach and outcome of paediatric patients with Chronic Non-Bacterial Osteomyelitis (CNO).

METHODS

Retrospective review of 30 children diagnosed with CNO at two tertiary care centres in Belgium. Imaging data were evaluated by blinded paediatric radiologists.

RESULTS

Mean age at onset was 10.3 years and mean age at diagnosis was 11.7 years. Bone pain was the leading symptom (29/30 patients). Out of 180 symptomatic lesions, 131 were confirmed on MRI as hyperintense geographic lesions on STIR images at the metaphysis and epiphysis adjacent to growth plates of tubular bones. The most common sites of involvement were the lower limbs, spine, sternoclavicular joint and humerus. For nearly half of the patients (14/30) monotherapy with NSAIDs was sufficient to obtain remission. The remaining 16 patients received second-line therapy: bisphosphonates (n = 15/30), disease-modifying antirheumatic drugs (n = 7/30), etanercept (n = 4/30) and tocilizumab (n = 1/30). Remission was reached after a mean time of 37.6 months in 26/30 patients. The prognosis was worse for patients with spinal involvement, resulting in more long-term sequelae.

CONCLUSIONS

We present a multicentre paediatric cohort of 30 CNO patients. A typical pattern of bone involvement could be found on MRI. NSAIDs were administered as first-line treatment. Second-line strategies included bisphosphonates, corticosteroids, methotrexate, etanercept and tocilizumab.

TRIAL REGISTRATION

Retrospectively registered. Registratienummer EC KUL: MP018023.

Whole-body magnetic resonance imaging findings and patterns of chronic nonbacterial osteomyelitis in a series of Greek pediatric patients

Background:

Chronic nonbacterial osteomyelitis (CNO) is a pediatric autoinflammatory disorder presenting with sterile inflammatory bone lesions. Whole-body MRI (WBMRI) has most recently emerged for disease assessment, but data are limited.

Purpose:

The purpose is to evaluate the imaging findings and patterns of CNO on WBMRI in a series of Greek pediatric patients.

Material and Methods:

Whole-body magnetic resonance imaging studies of all children with documented CNO, performed in a single tertiary center, were retrospectively reviewed. WBMRI included coronal T1 and short-tau inversion recovery (STIR), whole spine sagittal STIR, and ankle/foot sagittal STIR images. High signal intensity lesions on STIR images corresponding to bone marrow edema were recorded. The SPSS v.20 statistical package was used for descriptive statistics.

Results:

Twenty children were included (mean age: 12, range: 6–16 years) with 1–31 lesions (mean: 11.8) on WBMRI. Two children had unifocal disease localized at the clavicle, three paucifocal (1–4 lesions), and 15 multifocal bone involvement. All but two children presented with ankle pain and exhibited lesions at the bones of the ankle joint (90%) followed by the knee (50%) and pelvis (10%). The tibia was the most frequently affected bone (70%) followed by calcaneus (60%), fibula (50%), femur (45%), talus, and metatarsals (45%). No lesions in the cervical, thoracic, lumbar spine, and mandible were documented. Only small sacral lesions were seen in 25% of patients with the extensive peripheral disease. Bilateral metaphyseal and epiphyseal involvement with transphyseal extension were common, but the periosteal reaction and well-defined lesion margins were rare.

Conclusion:

Frequent involvement of the foot and ankle and paucity of substantial spinal involvement were seen in Greek pediatric patients with CNO.

MRI in the Diagnosis and Treatment Response Assessment of Chronic Nonbacterial Osteomyelitis in Children and Adolescents

PURPOSE OF REVIEW

To explain the central role of magnetic resonance imaging (MRI) in the diagnosis and follow-up of chronic nonbacterial osteomyelitis (CNO) in children and adolescents, centering on practical technical aspects and salient diagnostic features.

RECENT FINDINGS

In the absence of conclusive clinical features and widely accepted laboratory tests, including validated disease biomarkers, MRI (whether targeted or covering the entire body) currently plays an indispensable role in the diagnosis and therapy response assessment of CNO. Whole-body MRI, which is the reference imaging standard for CNO, can be limited to a short tau inversion recovery (STIR) coronal image set covering the entire body and a STIR sagittal set covering the spine, an approximately 30-min examination with no need for intravenous contrast or diffusion-weighted imaging. The hallmark of CNO is periphyseal (metaphyseal and/or epi-/apophyseal) osteitis, identified as bright foci on STIR, with or without inflammation of the adjacent periosteum and surrounding soft tissue. Response to bisphosphonate treatment for CNO has some unique MRI findings that should not be mistaken for residual or relapsing disease. Diagnostic features and treatment response characteristics of MRI in pediatric CNO are discussed, also describing the techniques used, pitfalls encountered, and differential diagnostic possibilities considered during daily practice.

Clinical characteristics and outcomes of chronic nonbacterial osteomyelitis in children: a multicenter case series

OBJECTIVE

The aim of this study was to evaluate demographic, clinical, laboratory, imaging, histopathology characteristics, and treatment responses of children with Chronic nonbacterial osteomyelitis (CNO).

METHODS

Retrospective multi-center case series study of pediatric patients diagnosed with CNO treated at five tertiary centers in south China.

RESULTS

Totally there were 18 patients diagnosed as CNO between 2014 and 2020. The median age of onset was 9.2 years (range 3.7-13.1) and 55.6% were female. Median delay in diagnosis was 10.9 months (range 1.0-72.0). The most frequent presenting symptoms were bone pain (100%) and fever (44.4%). Most patients had more than one lesion (median of 5, range 1-7). Most frequently affected bones were tibiofibula (88.9%) and femur (77.8%). The MRI characteristics mainly presented as bone edema and hyperintensity in bone marrow. Bone biopsy was conducted in 11 patients (61.1%) with inflammatory cells infiltration manifested as chronic osteomyelitis, and none showed bacterial infection or tumor. In treatment, non-steroid anti-inflamatory drugs (NSAIDs) is used as the first-line drug followed by steriods, methotexate (MTX), salazosulfadimidine (SASP), Bisphosphonates and TNF-α inhibitor. Two refractory cases received combination therapy with Bisphosphonates and TNF-α inhibitor, and achieved good therapeutic effect.

CONCLUSIONS

The present study described a multicenter series of CNO from south China and highlighted the clinical features, laboratory tests, imaging characteristics and treatment outcomes. Increasing awareness of this disease is important to decrease time to diagnosis, improve access to treatment, and reduce complications.

Ultrasound evaluation of inflammation in patients with chronic recurrent multifocal osteomyelitis involving the mandible: report of three cases

Chronic recurrent multifocal osteomyelitis (CRMO) is aseptic and can be diagnosed by excluding other diseases, such as bacterial osteomyelitis, scurvy, metabolic disorders, and malignant diseases; therefore, bone biopsy is usually performed to confirm the diagnosis. To prevent misdiagnosis, the appropriate timing and location for biopsy should be determined from an active phase of inflammation. We presented 3 cases of CRMO involving the mandible: Case 1: A 2-year-old girl diagnosed with CRMO in the chronic phase. A sonogram showed a slightly low echoic area adjacent to the bone cortex. Pathological examination revealed a slight accumulation of leukocytes and plasma cells, as well as predominant fibrous stroma. Case 2: A 9-year-old girl diagnosed with CRMO with massive new osteoid formation. A sonogram showed a massive inhomogeneous low echoic area adjacent to the bone cortex. Pathological examination revealed massive osteoid formation and scattered inflammatory cells infiltration. Case 3: A 3-year-old girl diagnosed with CRMO in the active phase. A sonogram showed a massive hypoechoic area adjacent to the bone cortex and hyperechogenicity associated with a muscular and subcutaneous edema. Pathological examination revealed massive bone destruction and neutrophils infiltration within damaged osteoid. Ultrasound was able to visualize the degree of inflammation in the mandible corresponding to that of the surrounding soft tissue in all 3 cases. Therefore, ultrasound would be useful in determining the appropriate timing and location for bone biopsy.

Bone and Joint Infections: The Role of Imaging in Tailoring Diagnosis to Improve Patients' Care

Imaging is needed for the diagnosis of bone and joint infections, determining the severity and extent of disease, planning biopsy, and monitoring the response to treatment. Some radiological features are pathognomonic of bone and joint infections for each modality used. However, imaging diagnosis of these infections is challenging because of several overlaps with non-infectious etiologies. Interventional radiology is generally needed to verify the diagnosis and to identify the microorganism involved in the infectious process through imaging-guided biopsy. This narrative review aims to summarize the radiological features of the commonest orthopedic infections, the indications and the limits of different modalities in the diagnostic strategy as well as to outline recent findings that may facilitate diagnosis.

Chronic Recurrent Multifocal Osteomyelitis and Its Management

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory disorder of bones first reported by Giedion et al. in 1972. It is a disease of childhood, comparable to SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) in adults. CRMO presents with pain and swelling overlying the involved bones. Inflammatory markers are usually raised and X-rays usually show sclerotic lesions. MRI demonstrates the extent of the lesions accurately and associated soft tissue changes. Nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are the mainstays of the management. We report three patients who presented with bone pains. Extensive workup and radiological modalities along with clinical findings supported the diagnosis of CRMO. This article highlights important clinical presentations, radiological findings, and various management options.

Whole-body MRI in pediatric undefined inflammatory conditions

BACKGROUND

Whole-body magnetic resonance imaging (WBMRI) is a multiregional imaging technique suitable for investigating the extent of multisystemic diseases without exposure to radiation, with a high sensitivity to bone alterations. The aim of our study was to evaluate the role of WBMRI in the workup of children with non-specific musculoskeletal features and non-indicative laboratory and instrumental data, who were suspected to have a rheumatologic disease.

METHODS

We retrospectively analyzed medical records, including laboratory tests and radiological data of 34 children who had been evaluated due to non-specific musculoskeletal manifestations, for which a WBMRI was prescribed.

RESULTS

We included 34 children, 19 females and 15 males, mean age 10 years (range 2-16 years), with the following clinical features: diffuse arthralgia (12 children), persistent fever (2 children), persistent fever and diffuse arthralgia (20 children). Serologic inflammatory markers were increased in 29/34 patients. Twenty-five children had already received X-ray and / or ultrasound before WBMRI, with a negative / uninformative result. WBMRI was performed 3-6 weeks (median, 3.5 weeks) after the initial presentation of symptoms. In 22/34 (65%) children, WBMRI revealed some abnormalities that supported the final diagnosis. Twelve out of 34 children (35%) were be affected by chronic recurrent multifocal osteomyelitis.

CONCLUSIONS

WBMRI is helpful in pediatric rheumatology for the differential diagnosis of undefined inflammatory conditions. It appears to be a promising tool, especially in the detection of multifocal bone lesions. The diagnosis that mainly benefits from WBMRI in our series is chronic recurrent multifocal osteomyelitis. WBMRI can also help in excluding neoplastic diseases.

Review of spinal involvement in Chronic recurrent multifocal osteomyelitis (CRMO): What radiologists need to know about CRMO and its imitators

Chronic recurrent multifocal osteomyelitis (CRMO) is a distinct disease entity of unknown etiology primarily affecting children and adolescents. It is an autoinflammatory process that typically affects multiple bones with a waxing and waning course. About one third of the patients diagnosed with CRMO have spinal involvement which can lead to long term morbidity. The clinical presentation and imaging features of CRMO involving the spine are nonspecific and can mimic other disease processes like infection or malignancy. Since imaging plays a very important role in the diagnosis and management of CRMO, we intend to highlight various imaging patterns of spinal CRMO alongside its clinical features and briefly discuss its imitators, management and outcomes.