SAPHO and Recurrent Multifocal Osteomyelitis

Molecular Imaging with PET-CT and PET-MRI in Pediatric Musculoskeletal Diseases

Molecular imaging has emerged as an integral part of oncologic imaging. Given the physiologic changes that precede anatomic changes, molecular imaging can enable early detection of disease and monitoring of response. [18F] Fluorodeoxyglucose (FDG) Positron emission tomography (PET) is the predominant molecular imaging modality used in oncologic assessment and can be performed using PET/CT or PET/MR. In pediatric patients, PET/MRI imaging is generally preferred due to low radiation exposure and PET/MRI is particularly advantageous for imaging musculoskeletal (MSK) diseases, as MRI provides superior characterization of tissue changes as compared to CT. In this article, we provide an overview of the typical role of PET CT/MRI in assessment of some common pediatric malignancies and benign MSK diseases with case examples. We also discuss the relative advantages of PET/MRI compared to PET/CT, and review published data with a primary focus on the use of PET/MR.

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.

Aseptic abscess associated with SAPHO syndrome: a case report

Aseptic abscess (AA) is a rare autoinflammatory disorder, characterized by the formation of sterile abscesses in various organs, and is accompanied by inflammatory bowel disease. Antibiotic treatment is ineffective, but steroid therapy shows a good response. AA can be difficult to differentiate from infection because abscesses appear similar both radiologically and histopathologically. Herein, we present the case of a 56-year-old woman with AA in the anterior chest wall and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

Chronic recurrent multifocal osteomyelitis causing optic neuropathy

We present the case of an 8-year-old girl with chronic recurrent multifocal osteomyelitis (CRMO) involving the orbit and facial bone and causing left optic neuropathy. She presented with intermittent left periorbital swelling and a history of CRMO diagnosed 5 years earlier. Her disease responded well to adalimumab; however, delayed presentation resulted in permanent unilateral optic nerve atrophy and reduced vision. Orbital inflammatory disease is a rare manifestation of CRMO, and early recognition of the disease and treatment may prevent irreversible vision loss.

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.

MR Imaging of Rheumatic Diseases Affecting the Pediatric Population

This article reviews the application of magnetic resonance imaging (MRI) to pediatric rheumatic diseases. MRI can detect early manifestations of arthritis, evaluate the extent of disease, and monitor disease activity and response to treatment.Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatic disorder, representing a diverse group of related diseases that share a definition of joint inflammation of unknown origin with onset before 16 years of age and lasting > 6 weeks. JIA may lead to significant functional impairment and is increasingly imaged with MRI to assess for active inflammation as a target for therapy. This is particularly true for juvenile spondyloarthritis that includes multiple subgroups of JIA and primarily involves the spine and sacroiliac joints.Other less common pediatric rheumatic diseases considered here are chronic recurrent multifocal osteomyelitis and collagen vascular diseases including polymyositis, dermatomyositis, scleroderma, and juvenile systemic lupus erythematosus.

Imaging of Pediatric Bone Tumors and Tumor-like Lesions

Bone lesions are commonly seen when reporting pediatric skeletal imaging. Distinguishing aggressive from nonaggressive lesions is essential in making the diagnosis. Not all aggressive lesions are neoplastic; indeed, osteomyelitis frequently presents with aggressive appearances and is far more commonly seen in the pediatric population than neoplastic lesions. In this article, we discuss an approach for the diagnosis of pediatric bone tumors and tumor-like conditions. The most common pediatric benign and malignant bone tumors are discussed in more detail.

Comparing children and adults with chronic nonbacterial osteomyelitis

PURPOSE OF REVIEW

To describe the main clinical differences of children and adults with chronic nonbacterial osteomyelitis (CNO).

RECENT FINDINGS

CNO is a severe systemic autoinflammatory syndrome characterized by multiple bone lesions because of inflammatory osteitis. Delay to diagnosis of CNO can lead to functional impairment, fractures, and chronic pain. Key clinical aspects and disease patterns differ in children and adults, including onset and time to diagnosis, symptom localization, associated comorbidities (i.e. skin, joints), bone lesion distribution pattern, and treatment approach. Novel biomarkers, such as urine N-terminal telopeptide in children and serum IgG4 in adults, are being studied for possible future use in improving diagnosis and guiding treatment. Despite recent advances in our understanding of CNO, many children and adults have a high disease burden and poor long-term outcomes. Recent findings suggest that adults with CNO tend to have a more chronic disease course and are less likely to achieve remission in follow-up.

SUMMARY

The clinical presentation of CNO differs in children and adults, highlighting the importance of these key features for the accurate diagnosis and early treatment in CNO.

Chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO)

Chronic nonbacterial osteomyelitis (CNO) is an inflammatory bone disorder that most frequently affects children and adolescents. Chronic recurrent multifocal osteomyelitis (CRMO) is a severe form of CNO, usually characterized by symmetrical inflammatory bone lesions and its waxing and waning character. Sometimes severe and chronic pain can significantly affect the quality of life and psychosocial development of individuals affected. In the absence of prospectively tested and widely accepted diagnostic criteria or disease biomarkers, CNO remains a diagnosis of exclusion, and infections, malignancy and other differentials require consideration (1). The pathophysiology of CNO is not fully understood, but imbalanced cytokine expression and increased inflammasome activation in monocytes from CNO patients contribute to a pro-inflammatory phenotype that contributes to bone inflammation (2). Currently, no medications are licensed for the use in CNO. Most patients show at least some response to nonsteroidal anti-inflammatory drugs, others require more aggressive treatment that can include corticosteroids, cytokine-blocking agents and/or bisphosphonates (3). While under the care of an experienced team and sufficient treatment, the prognosis is good, but some patients will develop sequalae which can include vertebral compression fractures (1).

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CNO is an autoinflammatory bone disorder mostly affecting children and adolescents.

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Dysregulated cytokine expression and pathological activation of inflammasomes play a central role.

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Treatment is based on experience from case series and expert consensus treatment plans.

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Understanding the exact molecular pathophysiology will allow patient stratification and individualized treatment.

Chronic Recurrent Multifocal Osteomyelitis of the Hand: A Rare Pediatric Condition

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory condition characterized by bone pain and swelling, secondary to sterile bone osteolytic lesions. Estimated incidence is 1:1 000 000, with ~2% involving the hand. We present a case series of CRMO of the hand and review the available literature, with the aim of educating and raising awareness of this condition. Methods: A retrospective chart review was conducted for all patients presenting to the institution diagnosed with CRMO involving the hands. Subsequently, a literature review was performed. Results/Case Series: Three cases of CRMO of the hand were identified. Age ranged from 20 months to 6 years, with 1 female. Time from presentation to diagnosis ranged from 3 to 15 months. Two had a single lesion, with the remaining patient having a second lesion on full-body magnetic resonance imaging (MRI). Three lesions involved phalanges, and one involved a metacarpal. Two received antibiotics without improvement prior to diagnosis. After diagnosis of CRMO, two received intravenous pamidronate. They both later showed improvement on MRI. Conclusion: CRMO is a rare disease with scarce literature to guide management. We present a series of CRMO specifically of the hand. The cases educate key stakeholders, raise awareness of the diagnosis, and illustrate challenging aspects of managing these patients. This includes the special functional and anatomical consideration essential in managing cases involving the hand.

Pathophysiology and MRI Findings of Infectious Spondylitis and the Differential Diagnosis

MRI에서 추간판의 이상 신호와 위, 아래 척추체 종판의 파괴, 종판 주변의 골수부종 등은 감염성 척추염의 전형적인 소견으로 여겨지나 퇴행성 척추질환, acute Schmorl's node, 척추관절병증, synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis, 척추신경관절병증, calcium pyrophosphate dehydrate 결절침착질환 등 다양한 비감염성 척추질환에서도 나타날 수 있다. MRI에서 이러한 비감염성 척추질환과 감별되는 감염성 척추염의 영상 소견은 추간판의 고신호와 농양, 척추 연부조직의 농양, 그리고 T1 강조영상에서 저신호로 보이는 종판의 경계가 불명확해지는 점 등이다. 그러나 이러한 감별점이 항상 적용되는 것은 아니며 감염성, 비감염성 질환의 영상 소견에 유사점이 많기 때문에 정확한 진단을 위해서는 감염성 척추염뿐만 아니라 감염과 감별해야 하는 다양한 질환의 병태생리와 연관된 영상학적 특징을 아는 것이 중요하다.

Mandibular involvement in SAPHO syndrome: a retrospective study

BACKGROUND

Mandible osteomyelitis can occur in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, a rare chronic inflammatory disease; however, few studies have explored its characteristics and management.

METHODS

We reviewed the medical records of consecutive SAPHO patients with mandible involvement diagnosed in Peking Union Medical College Hospital from September 2014 to July 2019. Demographic, clinical, laboratory, and imaging data were collected at baseline. Prescription data and follow-up magnetic resonance imaging (MRI) and cone beam computed tomography (CBCT) images were collected from the hospital information system. An electronic questionnaire was distributed to all patients to obtain their latest symptoms.

RESULTS

A total of 26 SAPHO patients with mandibular involvement were involved, all of whom responded to the questionnaire (38.5% male; median age, 28 years; median follow-up duration, 2.1 years). Ten patients (38.5%) had undergone an oral procedure 1 month before the onset of mandibular symptoms. All 14 of the patients who underwent a surgical intervention relapsed within a median duration of 2 months (range 0.25-4.0 months), and 24 patients (92.3%) achieved improvement with conservative treatment. Following bisphosphonate treatment, remission of bone marrow oedema and osteolysis was observed on MRI and CBCT, and 5 patients receiving bisphosphonates with follow-up CBCT after remission did not relapse in 5.4 months (mean 6.0, range 3.2-9.9 months).

CONCLUSION

Mandibular involvement of SAPHO syndrome predominantly occurs in young women. Dental procedures are a possible risk factor. Conservative treatment, especially intravenous bisphosphonates, can lead to oral improvement.

Chronic non-bacterial osteomyelitis masquerading as fibrous dysplasia

Chronic non-bacterial osteomyelitis is a rare auto-inflammatory bone disease seen predominantly in the paediatric population. We describe a unique case of a 30-year-old female who presented with right-sided jaw pain and intermittent swelling over the course of 6 years. She was initially treated with antibiotics for possible osteomyelitis, then temporarily diagnosed with fibrous dysplasia. She underwent extensive investigations consisting of an infectious workup, numerous imaging modalities, and three separate biopsies of her right jaw. She was ultimately diagnosed with chronic non-bacterial osteomyelitis based upon her history of recurrent episodes of painful swelling, response to non-steroidal anti-inflammatories, previously raised acute phase reactants, and magnetic resonance imaging findings. Unfortunately, she became refractory to non-steroidal anti-inflammatory therapy. Consequently, she was successfully treated with pamidronate, achieving clinical remission with improvement in her imaging findings. This case highlights the difficulty of diagnosis of chronic non-bacterial osteomyelitis and the need for increased awareness of the disease in the adult population. Additionally, the effective treatment with pamidronate supports the use of a bisphosphonate as an early intervention for adult-onset chronic non-bacterial osteomyelitis in patients who have failed non-steroidal anti-inflammatory therapy.

Imaging mimics of chronic recurrent multifocal osteomyelitis: avoiding pitfalls in a diagnosis of exclusion

Chronic recurrent multifocal osteomyelitis (CRMO) is a pediatric autoinflammatory disorder that is characterized by multiple sterile inflammatory bone lesions with a relapsing and remitting course. CRMO belongs to the autoinflammatory family of rheumatologic disorders based on absence of significant titers of autoantibodies and autoreactive T-lymphocytes. In absence of pathognomonic clinical, radiographic or pathological features, diagnosis can be challenging. CRMO shares imaging features with other diseases. It is important for radiologists to be able to differentiate other diseases from CRMO because prognosis varies from completely benign to frankly malignant. In this article we first present the clinical and imaging features of CRMO to help readers gain an understanding of the disease process, then discuss our imaging approach to CRMO and review other disease processes that sometimes share similar imaging findings to CRMO and review differentiating features to help avoid misdiagnoses.

Retinal vasculitis with Chronic Recurrent Multifocal Osteomyelitis: a case report and review of the literature

Background

Concurrent presentation of retinal vasculitis with mixed sclerotic and lytic bone lesions is rare.

Case presentation

We present the case of a 37-year old woman with a several year history of episodic sternoclavicular pain who presented for rheumatologic evaluation due to a recent diagnosis of retinal vasculitis. We review the differential diagnosis of retinal vasculitis, along with the differential diagnosis of mixed sclerotic and lytic bone lesions. Ultimately, bone marrow biopsy confirmed diagnosis of chronic recurrent multifocal osteomyelitis (CRMO). Concurrent presentation of CRMO with retinal vasculitis is extremely rare but important to recognize. The patient demonstrated clinical response to prednisone and tumor necrosis factor-alpha inhibition (TNF-i).

Conclusion

This case reports and unusual presentation of CRMO spectrum disease involving the sternum and sternoclavicular joint with concurrent retinal vasculitis.

Chronic non-bacterial osteomyelitis: a comparative study between children and adults

BACKGROUND

To compare clinical presentation, diagnostic and treatment strategies, and outcome between pediatric and adult patients with chronic non-bacterial osteomyelitis (CNO).

METHODS

Retrospective single-centre comparative study of pediatric and adult patients diagnosed with chronic recurrent multifocal osteomyelitis (CRMO)/CNO or synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome treated at the Medical University of Graz.

RESULTS

24 pediatric patients diagnosed with CRMO/CNO and 10 adult patients diagnosed with SAPHO syndrome were compared. Median age at diagnosis was 12.3 years (range 7.9-18.9) in the pediatric group and 32.5 years (range 22-56) in the adult group. Median time to diagnosis was shorter in children than in adults (0.3 vs. 1.0 years). Initial clinical presentation, laboratory and histopathological findings were similar in children and adults. Mean numbers of bone lesions were comparable between pediatric and adult patients (3.1 vs. 3.0), as were rates of skin involvement (33% vs. 30%). Sternal involvement was more frequent in adults whereas involvement of clavicle and long bones was more frequent in children (41.7% vs.10, 33% vs. 10%). Computerized tomography (CT) was used more often in adults, whereas whole-body magnetic resonance imaging (MRI) was used only in children. Bisphosphonates were applied more often in children and outcome was better in children than in adults (62.5% vs.30%).

CONCLUSION

Results of our study suggest that CNO/CRMO and SAPHO syndrome in children and adults might represent a single clinical syndrome that needs a similar diagnostic and therapeutic approach.

Total clavicle reconstruction with free peroneal graft for the surgical management of chronic nonbacterial osteomyelitis of the clavicle: a case report

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is a rare chronic autoinflammatory syndrome affecting mainly children and young adults. The natural history of the disease is marked by recurrent pain as the mainstay of inflammatory outbreaks. Typical radiographic findings are osteosclerosis and hyperostosis of the medial clavicle, sternum and first rib. Compression of the brachial plexus is exceedingly rare and one of the few surgical indications. Literature on total clavicle reconstruction is scarce. While claviclectomy alone has been associated with fair functional and cosmetic outcomes, several reconstruction techniques with autograft, allograft or even cement ("Oklahoma prosthesis") have been reported with the aim of achieving better pain control, cosmetic outcome and protecting the brachial plexus and subclavian vessels. We herewith report a unique case of complicated CNO of the clavicle treated with total clavicle reconstruction using a free peroneal graft.

CASE PRESENTATION

A 21-year-old female patient presented with CNO of her left clavicle, associated with recurrent, progressive and debilitating pain as well as limited range of motion. In recent years, she started complaining of paresthesia, weakness and pain radiating to her left arm during arm abduction. The clavicle diameter reached 6 cm on computed tomography, with direct compression of the brachial plexus and subclavian vessels. Following surgical biopsy for diagnosis confirmation, she further developed a chronic cutaneous fistula. Therefore, a two-stage total clavicle reconstruction using a vascularized peroneal graft stabilized by ligamentous reconstruction was performed. At two-year follow-up, complete pain relief and improvement of her left shoulder Constant-Murley score were observed, along with satisfactory cosmetic outcome.

CONCLUSIONS

This case illustrates a rarely described complication of CNO with direct compression of the brachial plexus and subclavian vessels, and chronic cutaneous fistula. To our knowledge, there is no consensus regarding the optimal management of this rare condition in this context. Advantages and complications of clavicle reconstruction should be carefully discussed with patients due to limited evidence of superior clinical outcome and potential local and donor-site complications. While in our case the outcomes met the patient's satisfaction, it remains an isolated case and further reports are awaited to help surgeons and patients in their decision process.

Chronic Non-bacterial Osteomyelitis: A Review

Chronic non-bacterial osteomyelitis (CNO) is a rare auto-inflammatory bone disorder, with a prevalence of around one in a million patients. In the more severe form, it is referred to as chronic recurrent multifocal osteomyelitis (CRMO). We present the current knowledge on epidemiology, pathophysiology as well as diagnostic options and treatment regimens. CNO/CRMO most commonly affects children and lesions are often seen in the metaphyseal plates of the long bones, but cases have been described affecting all age groups as well as lesions in almost every bone. It is, therefore, a disease that clinicians can encounter in many different settings. Diagnosis is mainly a matter of exclusion from differential diagnoses such as bacterial osteomyelitis and cancer. Magnetic resonance imaging is the best radiological method for diagnosis coupled with a low-grade inflammation and a history of recurring episodes. Treatment is based on case reports and consists of alleviating symptoms with non-steroidal anti-inflammatory drugs since the disease is often self-limiting. Recently, more active treatments using either bisphosphonates or biological treatment are becoming more common, to prevent long term bone damage. In general, due to its rarity, much remains unclear regarding CNO/CRMO. We review the known literature on CNO/CRMO and propose areas of interest as well as possible ways to make current diagnostic criteria more detailed. We also find unifocal cases of the jaw to be a possible sub-type that may need its own set of criteria.

Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography

The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.

Diagnostic value of ultrasonography in synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome: A case report

RATIONALE

Synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome is a rare condition that affects the skin, bones, and joints. Diagnosis of SAPHO syndrome is established based on clinical manifestations and imaging features on radiography or magnetic resonance imaging.

PATIENT CONCERNS

We report a 44-year-old male with a 20-year history of pustulosis who presented with pain in the lower extremities. Plain radiography demonstrated hyperostosis with subperiosteal erosions in the right tibia. Magnetic resonance imaging and computed tomography showed inflammatory accumulation, whereas musculoskeletal ultrasonography clearly depicted a periosteal reaction, osteitis, and enthesitis with abnormal blood flow in the surface of the right tibia.

DIAGNOSES

A diagnosis of SAPHO syndrome was made.

INTERVENTIONS

The patient was treated with combination therapy comprising prednisolone, methotrexate, and infliximab, which resulted in clinical improvement.

OUTCOMES

The elevated levels of C-reactive protein and matrix metalloproteinase-3 normalized, and the abnormal ultrasonographic findings disappeared.

LESSONS

The present case report demonstrates that multiple imaging modalities are important for the definitive diagnosis of SAPHO syndrome. Ultrasonography might be a useful tool for evaluating local musculoskeletal inflammation in patients with SAPHO syndrome.