Anterior chest wall in SAPHO syndrome: magnetic resonance imaging findings

A statistical symptomatic evaluation on SAPHO syndrome from 56 cases of confirmed diagnosis and 352 cases of non-SAPHO involvement

OBJECTIVE

To report a statistical evaluation of symptomatology based on 56 cases of SAPHO syndrome and 352 non-SAPHO involvement cases, to propose a symptomatic scoring system in consideration of early warning for SAPHO syndrome.

METHODS

A cohort comprising 56 subjects diagnosed with SAPHO syndrome was reported, as well as 352 non-SAPHO involvement cases, including their chief complaints, skin manifestations, radiological findings, and laboratory tests. We systematically reviewed previous published five representative huge cohorts from different countries to conclude several specific features of SAPHO by comparing with our case series. The score of each specific index is based on respective incidence and comparison of two cohorts was performed.

RESULT

In terms of complaint rates, all subjects of two cohorts suffered from osseous pain, which appeared in the anterior chest wall, spine, and limb which were calculated. In respect to dermatological lesions, SAPHO patients suffered from severe acne, and other patients (82.14%) accompanied with palmoplantar pustulosis. Having received radiological examinations, most SAPHO subjects rather than non-SAPHO involvement cases showed abnormal osteoarticular lesions under CT scanning and more detailed information under whole-body bone scintigraphy. Differences also emerged in elevation of inflammation values and rheumatic markers like HLA-B27. Based on our cases and huge cohorts documented, the early warning standard is set to be 5 scores.

CONCLUSIONS

SAPHO syndrome case series with 56 subjects were reported and an accumulative scoring system for the early reminder on SAPHO syndrome was proposed. The threshold of this system is set to be 5 points. Key Points • Fifty-six patients diagnosed by SAPHO syndrome with detailed symptoms and radiological findings were reported. • Comparison was made between the 56 SAPHO patients and 352 non-SAPHO involvement cases. • An accumulative scoring system for the early reminder on SAPHO syndrome was proposed and the threshold of this system is set to be five points.

Defining the imaging diagnostic criteria for adult chronic non-bacterial osteitis

Osteitis of the sternocostoclavicular (SCC) region, referred to as sternocostoclavicular hyperostosis (SCCH), is the clinical expression of chronic non-bacterial osteitis (CNO) in adults with this rare chronic auto-inflammatory disorder of the axial skeleton. The diagnosis is based on distinctive computerized tomography (CT) features of sclerosis and hyperostosis of the SCC region, and local increases in osteoid formation visualized by high radiopharmacon uptake on skeletal scintigraphy but clear radiologic diagnostic criteria are lacking. In a cross-sectional study, CT scans and whole-body skeletal scintigraphy images obtained in 169 patients seen at the Center for Bone Quality of the Leiden University Medical Center between 2008 and 2018 with a suspected diagnosis of CNO of the SCC region were re-evaluated by 2 skeletal radiologists and 2 nuclear physicians. The diagnosis was confirmed in 118 (70%) predominantly female patients (n = 103, 89.2%); median age at first symptoms 45 years (range 20-73). The diagnosis was excluded in the remaining 51 "non-CNO" patients. Increased radiopharmacon uptake at the SCC region was observed in 82% CNO patients, with the manubrium sterni having the highest predictive ability to discriminate on both imaging modalities. The prevalence of sclerosis of the clavicles, manubrium and first ribs was significantly higher in CNO patients (P < 0.001). Hyperostosis was not observed in non-CNO patients. 46 CNO versus only 2 non-CNO patients had costoclavicular ligament calcification. Our findings identify CT scan features of sclerosis and hyperostosis of manubrium sterni, medial end of clavicles and first ribs, and calcification of costoclavicular ligaments, associated with increased tracer uptake on skeletal scintigraphy at the SCC region, specifically manubrium sterni, as well-defined imaging diagnostic criteria for adult CNO. Pitfalls encountered in the diagnosis of CNO are highlighted. These defined imaging diagnostic criteria for adult CNO should facilitate the diagnosis of this rare auto-inflammatory bone disease across the spectrum of its early to late stages.

18F-Sodium fluoride PET-CT visualizes disease activity in chronic nonbacterial osteitis in adults

Chronic nonbacterial osteitis (CNO) is a rare disease spectrum, which lacks biomarkers for disease activity. Sodium fluoride-18 positron emission tomography/computed tomography ([18F]NaF-PET/CT) is a sensitive imaging tool for bone diseases and yields quantitative data on bone turnover. We evaluated the capacities of [18F]NaF-PET/CT to provide structural and functional assessment in adult CNO. A coss-sectional study was performed including 43 adult patients with CNO and 16 controls (patients referred for suspected, but not diagnosed with CNO) who underwent [18F]NaF-PET/CT at our expert clinic. Structural features were compared between patients and controls, and maximal standardized uptake values (SUVmax [g/mL]) were calculated for bone lesions, soft tissue/joint lesions, and reference bone. SUVmax was correlated with clinical disease activity in patients. Structural assessment revealed manubrial and costal sclerosis/hyperostosis and calcification of the costoclavicular ligament as typical features associated with CNO. SUVmax of CNO lesions was higher compared with in-patient reference bone (mean paired difference: 11.4; 95% CI: 9.4-13.5; p < .001) and controls (mean difference: 12.4; 95%CI: 9.1-15.8; p < .001). The highest SUVmax values were found in soft tissue and joint areas such as the costoclavicular ligament and manubriosternal joint, and these correlated with erythrocyte sedimentation rate in patients (correlation coefficient: 0.546; p < .002). Our data suggest that [18F]NaF-PET/CT is a promising imaging tool for adult CNO, allowing for detailed structural evaluation of its typical bone, soft-tissue, and joint features. At the same time, [18F]NaF-PET/CT yields quantitative bone remodeling data that represent the pathologically increased bone turnover and the process of new bone formation. Further studies should investigate the application of quantified [18F]NaF uptake as a novel biomarker for disease activity in CNO, and its utility to steer clinical decision making.

The clinical characteristics and prognosis of patients with SAPHO syndrome--a real-world cohort study

OBJECTIVES

We aimed to analyze the clinical characteristics and outcomes of patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

METHODS

The clinical records of 64 patients with SAPHO syndrome were collected, and the treatment and outcomes of 27 patients were followed up. The patients were divided into three groups according to the site of bone lesions: only anterior chest wall (ACW) involvement, only spinal involvement, and bone lesion involvement at both sites. The clinical characteristics and outcomes were compared. The clinical characteristics of the patients with and without peripheral joint involvement were compared.

RESULTS

Among all patients, 31.25% (20/64) had only ACW involvement, 15.63% (10/64) had only spinal involvement, and 53.12% (34/64) had both ACW and spinal involvement. Peripheral joint involvement was observed in 25.00% (16/64) of the patients. Patients with only spinal involvement were older than those with only ACW involvement (p = 0.006). Patients with both ACW and spinal involvement were older than those with only ACW involvement (p = 0.002) and had a longer diagnosis delay (p = 0.015). Patients with peripheral joint involvement were younger than those without peripheral joint involvement (p = 0.028). During follow-up, 88.89% (24/27) of patients had good outcomes. Twenty-two patients were treated with non-steroidal anti-inflammatory drugs + Iguratimod (IGU), and the outcomes of 90.91% (20/22) improved.

CONCLUSIONS

A relationship may exist between the sites of bone lesions and clinical characteristics of patients with SAPHO syndrome. The clinical outcomes of these patients may be good, and IGU may be effective in treating SAPHO syndrome. Key Points • This study is the first long-term follow-up on the effectiveness of iguratimod in treating patients with SAPHO. • This study revealed that patients with SAPHO and different bone lesion sites may present with different clinical characteristics.

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.

Prospective Comparison of the Imaging Value of 99m Tc-MDP Bone Scan and 68 Ga-FAPI-04 PET/CT in Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome

PURPOSE

This study aimed to explore the imaging value of 68 Ga-FAPI-04 PET/CT in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and compare it with that of 99m Tc-MDP bone scan.

METHODS

Nineteen participants with SAPHO syndrome underwent 68 Ga-FAPI-04 PET/CT and 99m Tc-MDP bone scan. Demographic data and clinical features were recorded, SAPHO imaging features were analyzed, and the osteoarticular lesion detection rate in both methods was calculated.

RESULTS

This prospective study recruited 4 men and 15 women aged 52.4 ± 8.6 years. The anterior chest wall was involved in all participants (100%). Palmoplantar pustulosis was the most common (36.8%) skin symptom. 99m Tc-MDP bone scan and 68 Ga-FAPI-04 PET/CT together detected 84 osteoarticular lesions, of which 91.7% (77/84) were detected by the former and 96.4% (81/84) by the latter. Furthermore, 68 Ga-FAPI-04 PET/CT detected 5 cases of knee and hip joint synovitis.

CONCLUSIONS

68 Ga-FAPI-04 PET/CT was more sensitive than 99m Tc-MDP bone scan when evaluating osteoarticular lesions in SAPHO syndrome and could also evaluate synovial lesions. 68 Ga-FAPI-04 PET/CT could be a good imaging method for SAPHO syndrome but requires further verification in a more extensive research cohort.

A Case Report on the Atypical Symptoms of the Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome: Could COVID-19 Be a Cause?

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, a rare disorder with a spectrum of manifestations and overlapping osseous and cutaneous symptoms, shares pathogenesis with various autoimmune diseases. SARS-CoV-2 has been previously linked to various autoimmune diseases like Guillain-Barré syndrome (GBS), a multi-inflammatory syndrome in children (MIS-C), or rheumatoid arthritis, but there is no existing work showing a link between SAPHO syndrome and COVID-19 yet. Here, we present a case of a middle-aged Asian male who presented with minimum swelling of his right second toe, 21 days post-COVID. After a series of investigations, namely, MRI scans, 99mTc-methylene diphosphonate three-phase bone scan, and bone biopsy, followed by a positive culture and sensitivity test of the same toe, a trial of vancomycin was given to the patient to treat bacterial osteomyelitis. This resulted in no improvement, pointing toward a misdiagnosis. A conclusion of sterile osteomyelitis of his right second and third metatarsal heads and phalanges due to SAPHO syndrome, as a possible complication of SARS-CoV-2 infection, was made. There are a number of classification systems for diagnosing this syndrome, one of which was modified by Kahn and was used in our case. Atypical presentations of rare disorders like SAPHO syndrome and their relation to SARS-CoV-2 infection are still to be fully discovered and investigated. Their prevention, timely diagnosis, and management may help in alleviating the discomfort and fear associated with the unknown for the patients.

Clinical and therapeutic diversity in adult chronic nonbacterial osteomyelitis (CNO) of the sternocostoclavicular region: a meta-analysis

OBJECTIVES

Chronic nonbacterial osteomyelitis (CNO) is a rare inflammatory bone disease. The distinct CNO subtype that affects the anterior chest wall is descriptively named sternocostoclavicular hyperostosis (SCCH) and mainly occurs in adults. Literature on CNO/SCCH is scattered and lacks diagnostic and therapeutic consensus.

METHODS

Systematic review and meta-analysis aiming to characterize clinical presentation and therapeutic modalities applied in adult CNO/SCCH patients. Untransformed numerical data and double-arcsine transformed proportional data were pooled in a random effects model in R-4.0.5; proportions were reported with 95% CI.

RESULTS

Forty studies were included, containing data on 2030 and 642 patients for aim 1 and 2, respectively. A female predisposition (67%, 95% CI 60, 73) and major diagnostic delay (5 years 95% CI 3, 7) were noted. Clinical presentation included chest pain (89%, 95% CI 79, 96) and swelling (79%, 95% CI 62, 91). Patients suffered from pustulosis palmoplantaris (53%, 95% CI 37, 68), arthritis (24%, 95% CI 11, 39) and acne (8%, 95% CI 4, 13). Inflammatory markers were inconsistently elevated. Autoantibody and HLA-B27 prevalence was normal, and histopathology unspecific. Increased isotope uptake (99%, 95% CI 96, 100) was a consistent imaging finding. Among manifold treatments, pamidronate and biologicals yielded good response in 83%, 95% CI 60, 98 and 56%, 95% CI 26, 85, respectively.

CONCLUSION

CNO/SCCH literature proves heterogeneous regarding diagnostics and treatment. Timely diagnosis is challenging and mainly follows from increased isotope uptake on nuclear examination. Biopsies, autoantibodies and HLA status are non-contributory, and biochemical inflammation only variably detected. Based on reported data, bisphosphonates and biologicals seem reasonably effective, but due to limitations in design and heterogeneity between studies the precise magnitude of their effect is uncertain. Fundamentally, international consensus seems imperative to advance clinical care for CNO/SCCH.

A case of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome with isolated lesions of the thoracic spine

We report a case of isolated lesions of the thoracic spine attributed to synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. A 55-year-old woman who suffered from 6 months of back pain had vertebral osteomyelitis on magnetic resonance imaging (MRI). There were no laboratory findings suggestive of infection, malignancy, or autoimmune disease. Radiography, computed tomography (CT), and MRI of the thoracic spine showed mixed lesions of sclerosis and erosion, whereas bone scintigraphy did not show accumulation at any site except the thoracic spine. No lesions in the anterior chest wall or sacroiliac joints were apparent from CT and MRI. No lesions other than at the thoracic spine were observed. As the isolated lesions of the thoracic spine were considered not to have resulted from infection, malignancy, or autoimmune disease, the patient was referred to our department for differential diagnosis. Given that isolated sterile hyperostosis/osteitis among adults is included in the modified diagnostic criteria for SAPHO syndrome, we suspected that the mixed lesions of sclerosis and erosion of the thoracic spine in this case may reflect SAPHO syndrome with chronic non-bacterial osteitis (CNO) of the thoracic spine. Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) was initiated and led to alleviation of her back pain, although the thoracic spine lesions remained on the 6-month MRI. Based on the CNO of the thoracic spine and the rapid response to NSAIDs, the final diagnosis was SAPHO syndrome with isolated lesions of the thoracic spine.

Pro and contra: is synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) a spondyloarthritis variant?

PURPOSE OF REVIEW

The purpose of this review is to present the up-to-date evidence on the epidemiology, pathogenesis, musculoskeletal manifestations, and imaging of the synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and to discuss its relationship with spondyloarthritis (SpA).

RECENT FINDINGS

SAPHO is a rare inflammatory disorder of bone, joints, and skin, with a worldwide distribution that predominantly affects the middle-age adults. The hallmark of the syndrome is a constellation of sterile inflammatory osteitis, hyperostosis, and synovitis involving the anterior chest wall, associated with acneiform and neutrophilic dermatoses, such as palmoplantar pustulosis and severe acne. The axial skeleton, sacroiliac, and peripheral joints can be involved in a similar fashion to SpA. The pathogenesis of the syndrome is multifactorial. The diagnosis is mainly based on the clinical and typical radiological features. The treatment approach is based on the off-label use of antibiotics, bisphosphonates, disease-modifying antirheumatic drugs, and anticytokine biologics.

SUMMARY

The SAPHO syndrome shares common features with SpA-related diseases, yet also shows some unique pathogenetic and clinical features. The nosology of SAPHO remains a subject of controversy, awaiting further research into the pathogenetic and clinical aspects of this syndrome. A better understanding of these aspects will improve the diagnostics and clinical care of patients with SAPHO.

SAPHO Syndrome and Pustulotic Arthro-Osteitis (PAO)

Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis (SAPHO) syndrome is a rare inflammatory osteo-articular disorder, which encompassed many diseases, including pustulotic arthro-osteitis (PAO). Bone and joint manifestations, including osteitis, synovitis and hyperostosis, are the hallmark of the SAPHO syndrome and affect a variety of regions of the body. Recent GRAPPA survey indicated that more than 80 percent of cases of SAPHO syndrome in Japan were thought to be PAO, originally proposed by Sonozaki et al. in 1981, whereas severe acne was the most commonly reported skin ailment amongst participants with SAPHO syndrome in Israel. SAPHO syndrome is a rare disease and adequate data regarding its prevalence remains unavailable, whereas prevalence of PPP was reported to be 0.12 % in Japan and 10-30% of patients with PPP had PAO. SAPHO syndrome and PAO are predominantly found in patients in the third through fifth decades of life, and a female predominance are seen in both groups. The diagnosis of SAPHO syndrome/PAO is typically made by a rheumatologist or dermatologist. Identification of a variety of the clinical, radiological, and laboratory features outlined, as well as diagnostic criteria, are used to make the diagnosis. Goals for treating patients with SAPHO syndrome/PAO seek to maximize health-related quality of life by improving skin and articular symptoms, preventing structural changes and destruction, and normalizing physical function and social participation. Finally, we review the non-pharmacological (ie: smoking cessation and controlling focal infections) and pharmacological managements including NSAIDs, bisphosphonates, cs DMARDs, bDMARDs, and other treatments for SAPHO syndrome/PAO.

Tripterygium wilfordii Hook F. in the treatment of synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome: a clinical trial

OBJECTIVE

This study aimed to investigate the efficacy and safety of Tripterygium wilfordii Hook F. (TwHF) in the treatment of osteoarticular lesions in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

METHODS

Eligible SAPHO patients were recruited to this single-center trial to receive 12-week TwHF treatment. Two dose groups (1.0-mg/kg/day group and 1.5-mg/kg/day group) were designed and patients were allocated (1:1) to these two groups. The primary endpoint was the change from baseline in Ankylosing Spondylitis Disease Activity Score on the basis of C-reactive protein level (ASDAS) at week 12.

RESULTS

All the 30 included patients completed the trial. At week 12, both dose groups showed significant change from baseline in ASDAS (1.0-mg/kg/day group: - 1.34 (1.10), p = 0.000; 1.5-mg/kg/day group: - 1.53 (1.19), p = 0.000). Similar improvement was also found in the Visual Analogue Scale in global osteoarticular pain, Bath Ankylosing Spondylitis Disease Activity Index, and other efficacy measures. The results showed a fast-acting characteristic of TwHF that the maximum efficacy was achieved within the first 2-4 weeks and maintained at a stable level for the rest of the study. No significant differences were observed between the two dose groups under the current sample size. TwHF was well tolerated that no severe adverse events or irregular menstruation were recorded, except for one patient who developed severe alanine aminotransferase elevation at the last follow-up and has stopped the TwHF treatment after the 12-week follow-up.

CONCLUSIONS

TwHF should be considered for the treatment of osteoarticular lesions in SAPHO syndrome in clinical practice because of significant efficacy, reliable safety, and high socioeconomic value.

TRIAL REGISTRATION

ChiCTR1900025912 Key points • This is the first clinical trial to evaluate Tripterygium wilfordii Hook F. (TwHF) in the treatment of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. • Twelve-week TwHF treatment in both dose groups designed (1.0-mg/kg/day group and 1.5-mg/kg/day group) was well tolerated and could lead to significant disease remission of SAPHO syndrome. • No significant differences were observed between the two dose groups under the current sample size. • TwHF should be considered for the treatment of osteoarticular lesions in SAPHO syndrome in clinical practice because of significant efficacy, reliable safety, and high socioeconomic value.