SAPHO Syndrome: MR Appearance of Vertebral Involvement

Current and future advances in practice: SAPHO syndrome and chronic non-bacterial osteitis (CNO)

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare, underdiagnosed disease with a wide clinical spectrum. Sterile bone inflammation, predominantly of the anterior chest, and skin manifestations (palmoplantar pustulosis, psoriasis vulgaris and acne) are the key features of SAPHO, which shares certain similarities with SpA. SAPHO is closely related to paediatric chronic non-bacterial osteitis (CNO), a spectrum of autoinflammatory bone diseases. The aetiology of SAPHO is considered multifactorial based on a complex interplay of genetic, immune and infectious factors. Despite the increasing awareness of SAPHO/CNO, diagnostic delay is common, as validated classification and diagnostic criteria are lacking. Treatment of SAPHO represents a challenge and includes anti-inflammatory drugs, antibiotics, bisphosphonates, synthetic conventional DMARDs and off-label use of anti-cytokine biologics and Janus kinase inhibitors. This review summarizes the current diagnostic and practical treatment approach to SAPHO/CNO and highlights the ongoing research endeavours concerning the definition and validation of diagnostic criteria, core domains and treatment.

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.

Imaging assessment of spine infection

This article comprehensively reviews current imaging concepts in spinal infection with primary focus on infectious spondylodiscitis (IS) as well as the less common entity of facet joint septic arthritis (FSA). This review encompasses the multimodality imaging appearances (radiographs, CT, MRI, and nuclear imaging) of spinal infection-both at initial presentation and during treatment-to aid the radiologist in guiding diagnosis and successful management. We discuss the pathophysiology of spinal infection in various patient populations (including the non-instrumented and postoperative spine) as well as the role of imaging-guided biopsy. We also highlight several non-infectious entities that can mimic IS (both clinically and radiologically) that should be considered during image interpretation to avoid misdiagnosis. These potential mimics include the following: Modic type 1 degenerative changes, acute Schmorl's node, neuropathic spondyloarthropathy, radiation osteitis, and inflammatory spondyloarthropathy (SAPHO syndrome).

Whole-Body Magnetic Resonance Imaging in Rheumatology

This review focuses on the most frequent whole-body MRI applications in patients with rheumatological pathologies, for which this tool can be helpful to both radiologists and clinicians. It reports technical aspects of the acquisition of both 1.5 and 3.0 T scanners. The article lists the main findings that help radiologists during the evaluation of a specific pathology, both in the diagnostic phase and during follow-up.

Imaging of Spondylodiscitis: A Comprehensive Updated Review-Multimodality Imaging Findings, Differential Diagnosis, and Specific Microorganisms Detection

Spondylodiscitis is defined by infectious conditions involving the vertebral column. The incidence of the disease has constantly increased over the last decades. Imaging plays a key role in each phase of the disease. Indeed, radiological tools are fundamental in (i) the initial diagnostic recognition of spondylodiscitis, (ii) the differentiation against inflammatory, degenerative, or calcific etiologies, (iii) the disease staging, as well as (iv) to provide clues to orient towards the microorganisms involved. This latter aim can be achieved with a mini-invasive procedure (e.g., CT-guided biopsy) or can be non-invasively supposed by the analysis of the CT, positron emission tomography (PET) CT, or MRI features displayed. Hence, this comprehensive review aims to summarize all the multimodality imaging features of spondylodiscitis. This, with the goal of serving as a reference for Physicians (infectious disease specialists, spine surgeons, radiologists) involved in the care of these patients. Nonetheless, this review article may offer starting points for future research articles.

Imaging of bone marrow pitfalls with emphasis on MRI

Normal marrow contains both hematopoietic/red and fatty/yellow marrow with a predictable pattern of conversion and skeletal distribution on MRI. Many variations in normal bone marrow signal and appearances are apparent and the reporting radiologist must differentiate these from other non-neoplastic, benign or neoplastic processes. The advent of chemical shift imaging has helped in characterising and differentiating more focal heterogeneous areas of red marrow from marrow infiltration. This review aims to cover the MRI appearances of normal marrow, its evolution with age, marrow reconversion, variations of normal marrow signal, causes of oedema-like marrow signal, and some common non-neoplastic entities, which may mimic marrow neoplasms.

Imaging of Spine Infections

The incidence of spondylodiskitis has increased over the last 20 years worldwide, especially in the immunodepressed population, and it remains a complex pathology, both in terms of diagnosis and treatment. Because clinical symptoms are often nonspecific and blood culture negative, imaging plays an essential role in the diagnostic process. Magnetic resonance imaging, in particular, is the gold standard technique because it can show essential findings such as vertebral bone marrow, disk signal alteration, a paravertebral or epidural abscess, and, in the advanced stage of disease, fusion or collapse of the vertebral elements. However, many noninfectious spine diseases can simulate spinal infection. In this article, we present imaging features of specific infectious spine diseases that help radiologists make the distinction between infectious and noninfectious processes.

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.

Beyond the sacro-Iliac joints: Vertebral involvement in axial spondylarthritis

Imaging plays a central role in the diagnosis of axial spondylarthritis (axSpA). Commonly the sacroiliac joints are involved but vertebral involvement can occur in isolation in 1 out of 4 patients. Recognizing vertebral involvement patterns in axSpA can help establishing a diagnosis early and initiate therapy before irreversible changes have occurred. Magnetic resonance imaging (MRI) is considered the reference standard for early detection of inflammatory changes of the disease. Aims of this review are to present an overview of the imaging findings of vertebral involvement in axSpA, and to detail the current recommendations on the role of imaging in the diagnosis of axSpA in patients with isolated vertebral involvement.

[Spondylodiscitis and epidural abscesses]

CLINICAL/METHODOLOGICAL PROBLEM

Spondylodiscitis is an inflammation of the intervertebral disc, which in adults is generally associated with spondylitis of the adjacent vertebrae. It often presents clinically with nonspecific symptoms such as back or neck pain. It may be caused by various pathogens, especially bacteria. One or more vertebral segments can be affected. The infection can spread to surrounding compartments and can lead to epidural abscesses. Radiology, in particular magnetic resonance imaging (MRI), plays an important role in the diagnostic work-up and in the follow-up to monitor response to therapy. Treatment consists of conservative (antibiotics) and invasive approaches, including surgery. Interventional puncture and drainage is a promising alternative to surgery, especially in early stages of abscess formation.

STANDARD RADIOLOGICAL METHODS

Magnetic resonance imaging (MRI), computed tomography (CT), nuclear medical procedures, conventional x‑ray.

PERFORMANCE

MRI has the highest value. CT and nuclear medical procedures can be used as a supplement to MRI and in patients with contraindications for MRI.

PRACTICAL RECOMMENDATIONS

With adequate diagnosis and therapy, spondylodiscitis has a good prognosis. In addition to targeted or calculated drug therapy, invasive treatment is the main focus, especially for epidural abscesses. Interventional radiological drainage can represent a less invasive alternative to surgical treatment.

Comparative analysis and differentiation between SAPHO syndrome and spondyloarthropathies using whole-spine MRI

AIM

To determine the imaging characteristics of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome and seronegative spondyloarthropathies (SpAs) on whole-spine magnetic resonance imaging (WS-MRI) and evaluate the role of WS-MRI in the diagnosis and differentiation of the two diseases.

MATERIALS AND METHODS

Twenty-eight patients with SAPHO and 44 with SpAs were included. All patients were symptomatic and clinically diagnosed with SAPHO or SpAs, and all underwent WS-MRI for comparison of imaging characteristics.

RESULTS

The mean age of the SAPHO patients was 48.7 ± 12.7 years, while that of the SpA patients was 34.7 ± 12.3 years (p<0.001). WS-MRI showed that the frequency of cervical, thoracic, and lumbar spine involvement was 53.6% versus 52.3%, 75% versus 88.6%, and 60.7% versus 63.6%, respectively (p=0.70, 0.13, and 0.80). The frequency of sacroiliac joint involvement was 7.1% and 100% (p<0.001). Continuous spinal involvement accounted for 50% versus 43.2%, 60.7% versus 84.1%, and 39.3% versus 40.9% in the cervical, thoracic, and lumbar vertebrae, respectively (p=0.03). WS-MRI showed that bone marrow oedema of spinal anterior corner was observed in 50% versus 75% (p=0.03). Vertebral body and posterior attachment involvement accounted for 85.7% versus 93.2% and 14.3% versus 34.1% (p=0.3, 0.06). The frequency of bone erosion in mobile spine was 75% and 36.4%, respectively (p=0.02). The frequency of intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue swelling was 42.9% versus 18.2%, 53.6% versus 22.7%, 85.7% versus 42.2%, and 50% versus 11.4% (p=0.02, 0.00).

CONCLUSIONS

Factors differentiating the two groups at WS-MRI were bone marrow oedema of the spinal anterior corner, bone erosion, and swelling of the intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue.

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.

The Genetic Architecture of High Bone Mass

The phenotypic trait of high bone mass (HBM) is an excellent example of the nexus between common and rare disease genetics. HBM may arise from carriage of many 'high bone mineral density [BMD]'-associated alleles, and certainly the genetic architecture of individuals with HBM is enriched with high BMD variants identified through genome-wide association studies of BMD. HBM may also arise as a monogenic skeletal disorder, due to abnormalities in bone formation, bone resorption, and/or bone turnover. Individuals with monogenic disorders of HBM usually, though not invariably, have other skeletal abnormalities (such as mandible enlargement) and thus are best regarded as having a skeletal dysplasia rather than just isolated high BMD. A binary etiological division of HBM into polygenic vs. monogenic, however, would be excessively simplistic: the phenotype of individuals carrying rare variants of large effect can still be modified by their common variant polygenic background, and by the environment. HBM disorders-whether predominantly polygenic or monogenic in origin-are not only interesting clinically and genetically: they provide insights into bone processes that can be exploited therapeutically, with benefits both for individuals with these rare bone disorders and importantly for the many people affected by the commonest bone disease worldwide-i.e., osteoporosis. In this review we detail the genetic architecture of HBM; we provide a conceptual framework for considering HBM in the clinical context; and we discuss monogenic and polygenic causes of HBM with particular emphasis on anabolic causes of HBM.

Anterior chest wall in SAPHO syndrome: magnetic resonance imaging findings

BACKGROUND

The anterior chest wall (ACW) involvement is characteristic of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, yet little research has focused on its magnetic resonance imaging (MRI) findings.

PURPOSE

To characterize the MRI features of the ACW in patients with SAPHO syndrome.

METHODS

Seventy-one patients with SAPHO syndrome and ACW involvement evidenced by bone scintigraphy were recruited in this cross-sectional study. The ACW region was scanned using sagittal, axial, and oblique coronal Dixon T2-weighted sequences and axial Dixon T1-weighted sequences. The characteristics of both active inflammatory and chronic structural lesions were evaluated.

RESULTS

The ACW lesions exhibited an asymmetrical distribution and a predilection for the sternocostoclavicular region (93.0%). Notably, 91.5% of the patients had lesions in the area of the anterior first ribs. Bone marrow edema (BME) was observed in 63 (88.7%) patients, which mainly affected the sternocostal joints (87.3%) and the manubrium sterni (84.5%). All of the BMEs were distributed under the articular surface or the bone cortex, consistent with the distribution of the ligaments and joint capsules. Synovitis was detected in 64 (90.1%) patients, with a predilection for the sternoclavicular joints (76.1%). A soft tissue mass or infiltration was found in all the patients who had bone marrow edema. Thirteen (18.3%) patients showed venous stenosis. Structural changes included bone bridge formation (80.3%), hyperostosis (43.7%), and fat infiltration (39.4%). Four common patterns of involvement were observed: the first rib area, the sternoclavicular area, the sternal angle area, and the areas of the second to sixth sternocostal joints.

CONCLUSION

The ACW lesions of SAPHO syndrome demonstrated a triad of enthesitis, synovitis, and osteitis, suggesting complex interactions among the ligaments, synovium, and bones in the region. The inflammatory changes in the first rib area were highlighted in SAPHO syndrome.

Axial skeletal lesions and disease duration in SAPHO syndrome: A retrospective review of computed tomography findings in 81 patients

AIMS

To explore the relevance of disease duration with axial skeletal lesions in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome based on computed tomography (CT).

METHODS

Patients who had undergone whole-spine CT were included from a previously reported single-center cohort of SAPHO syndrome. Patients with previous treatments of bisphosphates, biological agents or surgeries were excluded. Sites of axial skeletal involvement were reviewed including the spine, sacroiliac joints, and anterior chest wall. Duration of osteoarticular involvement was defined as the interval between the onset of osteoarticular symptoms and the CT evaluation.

RESULTS

Eighty-one patients (54 female and 27 male) were included in the study. The mean disease duration was 26.9 ± 34.9 months. Fifty (63.0%) patients showed spinal lesions on CT. The average numbers of involved vertebral segments for corner and endplate lesions were 3.16 ± 3.51 and 0.73 ± 1.85 respectively. Sixty-eight (84.0%) patients exhibited abnormalities in the anterior chest wall. The number of involved vertebral segments showed poor correlation with disease duration for both corner lesions (r²  = 0.051, P = 0.043) and endplate lesions (r²  = 0.137, P = 0.001). Patients with costoclavicular involvement showed remarkably longer disease duration than those without (49.3 ± 47.7 months vs 18.0 ± 23.5 months, P = 0.006), while no significant difference was detected regarding other structures in the anterior chest wall.

CONCLUSION

Costoclavicular involvement is a hallmark of long disease duration in SAPHO syndrome. Corner and endplate lesions in the vertebrae and sacroiliac involvement may not relate to disease course.

The comparison analysis of clinical and radiological features in SAPHO syndrome

OBJECTIVES

The aim was to comparatively assess the clinical and imaging features in patients with SAPHO syndrome.

METHODS

The clinical data, laboratory results, imaging data of forty-six SAPHO patients were reviewed and the SAPHO patients were divided into spinal involvement group and non-spinal involvement group. Fifty patients with ankylosing spondylitis were recruited as control group. The clinical and radiological features of them were analyzed and compared.

RESULTS

Thirty-four of 46 (73.9%) of all the SAPHO patients had spinal involvement. The lesions exhibited as abnormal hyper-intensity signal in vertebral bodies, vertebral body erosion or collapse, bone marrow edema, endplate inflammation, spondyldiscitis, paravertebral ossification, and facet joint involvement. Compared with patients in non-spinal involvement group, the age at disease onset was older (P = 0.033), the disease duration was longer (P = 0.048), and CRP level was elevated (P = 0.047) in patients in spinal involvement group. Compared with patients with ankylosing spondylitis, SAPHO patients were more likely to have cervical vertebra involvement (P = 0.024), endplate inflammation (P = 0.019), and spondyldiscitis (P = 0.001), but less multiple vertebral body and facet joint involvement (P = 0.002). Patients regularly received DMARDS or biologics treatment had symptoms relieved and lesions turned into chronic stage or better than before.

CONCLUSIONS

A total of 73.9% of the SAPHO patients had spinal involvement and the involvement could affect any part of the spine. Cervical vertebral involvement, endplate inflammation, and sponlypodiscitis were more common in SAPHO than in patients with ankylosing spondylitis. In SAPHO patients with spinal involvement, the disease duration was longer and the inflammatory reaction was more intensive. DMARDs and biologics may help to prevent the disease progress.

KEY POINTS

• To the best of our knowledge, this paper is the first one to comparatively study the clinical and radiological features of SAPHO syndrome, especially the characteristics of spinal involvement.

Pamidronate in chronic non-bacterial osteomyelitis: a randomized, double-blinded, placebo-controlled pilot trial

OBJECTIVE

This is the first randomized double-blinded, placebo-controlled pilot trial to investigate the efficacy of pamidronate in reducing radiological and clinical disease activity in chronic non-bacterial osteomyelitis (CNO).

METHOD

Patients received pamidronate or placebo at baseline and weeks 12 and 24. Whole-body magnetic resonance imaging was performed at baseline and weeks 12 and 36, and computed tomography of the anterior chest wall (ACW) at baseline and week 36. Radiological disease activity was systematically scored in the ACW and spine. Patient-reported outcomes [visual analogue scale (VAS) pain, VAS global health, Health Assessment Questionnaire (HAQ), EuroQol-5 Dimensions (EQ-5D), and 36-item Short-Form Health Survey (SF-36)] and biomarkers of bone turnover and inflammation were assessed at baseline and weeks 1, 4, 12, 24, and 36. Data are expressed as median [interquartile range].

RESULTS

Fourteen patients were randomized and 12 were analysed. From baseline to week 36, the radiological disease activity score in the ACW decreased from 5 [4-7] to 2.5 [1-3] in the pamidronate group, but did not change in the placebo group (p = 0.04). From baseline to week 36, VAS pain and VAS global health tended to decrease more in the pamidronate than in the placebo group (p = 0.11, p = 0.08). Physical functioning (HAQ) and health-related quality of life (EQ-5D, SF-36) did not change. Biomarkers of bone turnover decreased only in the pamidronate group (p ≤ 0.02).

CONCLUSION

Pamidronate may improve radiological and clinical disease activity in CNO. Methods to score radiological disease activity in adult CNO were suggested. Clinical Trials: NCT02594878.

Imaging for Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome

Multifocal osteomyelitis and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome constitute a spectrum of disease that includes inflammatory bone lesions and dermatologic findings. Radiographic features resemble those of the spondyloarthropathies with anterior chest wall involvement. Early radiographic findings are osteodestructive with lytic lesions. Bone scintigraphy of the sternoclavicular region classically yields a 'bull's head' pattern of radionuclide uptake. Magnetic resonance imaging (MRI) can demonstrate corner lesions of vertebral bodies. Ultrasound often reveals peripheral enthesitis. Late radiographic features are usually osteoproliferative. PET/CT can identify chronic lesions. Differential diagnostic considerations include osteomyelitis and malignancy, which often prompt bone biopsy.

Clinical heterogeneity of SAPHO syndrome: challenging diagnose and treatment

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare disease which is often misdiagnosed and under-recognized, because of its peculiar and heterogeneous clinical presentation. Its main features consist of cutaneous and osteoarticular manifestations, the latter affecting more often the anterior chest wall and having typical radiologic findings. There are no validated diagnostic criteria for SAPHO and no guidelines for treatment, due mainly to its rarity; as a consequence, therapy is empirical and aimed to control pain and modifying inflammatory process. To date, the use of anti-TNF agents has been proved to be a valid alternative for patients unresponsive to conventional treatments, such as NSAIDs, corticosteroids, DMARDs and biphosphonates. The clinical heterogeneity of the disease, possibly due to differences in pathogenic mechanism of different manifestations, is challenging for both diagnosis and treatment, which should aim to control both skin and bone involvement in different clinical subsets. Here, we summarize the current status of knowledge about the SAPHO syndrome and present two cases of patients with very different disease manifestations, suggesting the need for personalized treatment.

Whole-spine Computed Tomography Findings in SAPHO Syndrome

OBJECTIVE

We evaluated the whole-spine computed tomography (CT) findings in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome to improve our understanding of this rare disease.

METHODS

Whole-spine CT images obtained in 69 patients with SAPHO were reviewed. For each individual, a total of 25 vertebrae were evaluated for the distribution of affected vertebrae, CT manifestations of vertebral lesions, symmetry and location of distribution of the lesions on vertebrae, involvement pattern, and narrowing of adjacent intervertebral disc space. Paravertebral ligamentous ossifications, apophyseal joint disorders, and costovertebral joint disorders were also evaluated.

RESULTS

All the 69 patients with SAPHO exhibited abnormalities on whole-spine CT. Sixty-four had vertebral lesions, 52 had paravertebral ossifications, and 47 had both. The vertebral lesions were observed in 441 vertebrae, with a predilection for thoracic spine. The lesions exhibited a mixture of cortical erosion, reactive osteosclerosis of surrounding cancellous bone, and syndesmophyte. They may be confined to the vertebral corner (65.1%) or be extensive, involving the endplate (34.9%). Corner lesions could start in any part of the epiphyseal ring. The lesions were asymmetrically distributed. The affected vertebrae were more consecutively involved in a "kissing" appearance (78.2%). Intervertebral disc spaces were usually normal or mildly narrowed. There were 320 foci of paravertebral ossifications observed, with a predilection for the supraspinous ligament. Paravertebral ossifications were delicate and segmental. Ossifications throughout annulus fibrosis and apophyseal joint were not observed.

CONCLUSION

Our investigation of the distributional, morphological features and the involvement pattern of spinal lesions in patients with SAPHO demonstrated distinct CT characteristics.

The coexistence of SAPHO syndrome and rheumatoid arthritis: A case report

RATIONAL

SAPHO (Synovitis-Acne-Pustulosis-Hyperstosis-Osteitis) syndrome is a rare disease featured by its dermatological and osteoarthritic disorders, the latter of which mainly affecting the anterior chest wall, spine, and sacroiliac joint. However, rheumatoid arthritis (RA) is a chronic autoimmune disease, mainly affecting the synovial tissue of small joints in hands and feet. Here, we present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. So far, only 1 similar case has been reported in the English literature.

PATIENT CONCERNS

In Sep 2015, a 59-year-old female patient presented to our hospital, complaining of refractory low back pain, left sternoclavicular joint pain, and palmoplanar pustulosis (PPP). In addition, RA had been diagnosed 10 years earlier in the patient, manifested as pain and swelling in bilateral hands and wrists, accompanied by morning stiffness, as well as positive serologic tests.

INTERVENTIONS

In our hospital, laboratory tests revealed elevated inflammatory markers, and imaging examinations of relevant sites showed specific osteoarthritic lesions for SAPHO syndrome.

DIAGNOSES

These findings lead us to make an easy diagnosis of the coexistence of SAPHO syndrome and RA in this petient.

OUTCOMES

Treatment with tripterygium wilfordii polyglycosidium and prednisone was introduced. Both dermatological and osteoarthritic symptoms improved during a 3-month follow-up. Symptoms of RA were successfully controlled with prednisone and leflunomide since 2005.

LESSONS

We present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. With this case report, we want to draw attention to the diverse features of SAPHO syndrome.

Multimodal imaging findings of SAPHO syndrome with no skin lesions: A report of three cases and review of the literature

Synovitis, acne, palmoplantar pustulosis, hyperostosis and osteitis syndrome (SAPHO) is a rare syndrome that affects the skin, bones and joints. Diagnosis of SAPHO syndrome is established on clinical appearance and imaging features. The present case report described the imaging features of three cases of SAPHO with sternoclavicular joint arthritis but without skin manifestations using multiple imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and bone scintigraphy. The first case was a 52-year-old male who suffered from progressive sternoclavicular arthritis for 2 years. The second case was a 62-year-old female with arthritis in the larger joints for 5 years, particularly on the right thoracic area. The third case was a 44-year-old male who exhibited a slight bulge accompanied by pain in the upper anterior chest wall for 4 years. All of them lacked cutaneous lesions. CT demonstrated sclerosis and hyperostosis with subchondral erosions in the sternocostoclavicular joints. MRI revealed bone marrow edema that was slightly hypointense on T1-weighted imaging, and hyperintense on T2-weighted imaging. Typical 'bull head' signs were observed in bone scintigraphy images. The present case study demonstrated that SAPHO syndrome should be suspected in patients with multifocal osteitis or arthritis affecting the chest wall that lack skin manifestations. Multimodal imaging modalities in combination are helpful for SAPHO diagnosis.

SAPHO Syndrome: Imaging Findings of Vertebral Involvement

BACKGROUND AND PURPOSE

Imaging findings in patients with a combination of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) are often misinterpreted as discitis/osteomyelitis or metastases, resulting in multiple biopsies and delayed diagnosis. We have incidentally noted a semicircular morphology in vertebral body imaging in several cases of SAPHO syndrome with vertebral involvement. Our goal was to evaluate the prevalence of this distinctive morphology in these patients.

MATERIALS AND METHODS

A retrospective review of patients with SAPHO syndrome diagnosed between July 1998 and August 2013 was conducted. A descriptive analysis of MR imaging, CT, radiography, bone scanning, and PET imaging was performed for the presence and distribution of vertebral body signal intensity or attenuation changes and/or enhancement; contiguous vertebral body involvement; vertebral body collapse; endplate irregularity; disc space, facet, and spinous process involvement; subligamentous thickening; and paraspinal soft-tissue involvement.

RESULTS

Eighteen patients (16 women [89%]; mean age, 52.9 years) with SAPHO and spine involvement were included. Contiguous involvement of ≥2 vertebral bodies was found in 16 patients (89%), with a curvilinear or "semicircular" pattern involving portions of adjacent vertebral bodies in 10 (63%, P = .14). Most intervertebral discs demonstrated absence of abnormal T2 hyperintensity (73%) and enhancement (89%). Subligamentous thickening was present in 12 (67%). Paraspinal soft-tissue involvement was present in 6 (33%).

CONCLUSIONS

SAPHO syndrome should be included in the differential diagnosis in a patient with a curvilinear or semicircular pattern of vertebral involvement, contiguous vertebral body involvement, and absence of intervertebral disc edema and enhancement.

Syndromes with chronic non-bacterial osteomyelitis in the spine

Chronic non-bacterial osteomyelitis (CNO) has been known for over of 40 years. It is an underrecognized entity due to the low number of described cases and poor propagation awareness of the problem. Chronic non-bacterial osteomyelitis is usually confused with infectious spondylodiscitis or malignant lesions, both primary and metastatic. Failing to consider CNO as one of possible lesions of the spine among an array of differential diagnoses may lead to a prolonged ineffective treatment increasing treatment-related morbidity. In this paper the authors describe these two syndromes, with a possible autoimmune background – chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO syndrome – that include CNO being among the manifestations. The authors present the spinal symptomatology of CNO for both syndromes published so far to help spine clinicians organize the information for better usage in everyday clinical practice.

Pyogenic spinal infections

Spinal infections are a spectrum of disease comprising spondylitis, diskitis, spondylodiskitis, pyogenic facet arthropathy, epidural infections, meningitis, polyradiculopathy, and myelitis. Inflammation can be caused by pyogenic, granulomatous, autoimmune, idiopathic, and iatrogenic conditions. In an era of immune suppression, tuberculosis, and HIV epidemic, together with worldwide socioeconomic fluctuations, spinal infections are increasing. Despite advanced diagnostic technology, diagnosis of this entity and differentiation from degenerative disease, noninfective inflammatory lesions, and spinal neoplasms are difficult. Radiological evaluations play an important role, with contrast-enhanced MR imaging the modality of choice in diagnosis, evaluation, treatment planning, interventional treatment, and treatment monitoring of spinal infections.

The SAPHO syndrome revisited with an emphasis on spinal manifestations

The synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome includes a group of chronic, relapsing, inflammatory musculoskeletal disorders with similar manifestations, in particular synovitis, hyperostosis, and osteitis, which may or may not be associated with neutrophilic skin eruptions such as palmoplantar pustulosis and acne conglobata. The syndrome occurs at any age, can involve any skeletal site, and its imaging appearances are variable, depending on the stage/age of the lesion and imaging method. The diagnosis is difficult if there is no skin disease. Awareness of the imaging appearances, especially in the spine, may help the radiologist in avoiding misdiagnosis (e.g., infection, tumor) and unnecessary invasive procedures, while facilitating early diagnosis and selection of an effective treatment. In this article, we provide an overview of the radiological appearances of SAPHO syndrome, focusing on the magnetic resonance imaging findings of vertebral involvement, and present relevant clinical and pathological features that assist early diagnosis.

Diagnosis and treatment of SAPHO syndrome: A case report

The present study reports a rare case of synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome in an adult male. The 42-year-old man complained of skin lesions, chest pain and lumbago. Laboratory evaluations demonstrated an elevated erythrocyte sedimentation rate and increased levels of C-reactive protein. Computerized tomography, bone scintigraphy and magnetic resonance imaging revealed multiple bone lesions. A diagnosis of SAPHO syndrome was made. Non-steroidal anti-inflammatory drugs, alendronate sodium and steroids were administered, which resulted in clinical improvement. The current case study demonstrates that skin manifestation and multiple imaging modalities are important in generating a definite diagnosis of SAPHO syndrome, and that early treatment is vital for a positive outcome.

Sclerotic lesions of the spine: MRI assessment

Sclerotic (T2 dark) lesions of the spine are infrequent and, as a result, these are often missed or misdiagnosed. Plain films may not be always available during magnetic resonance imaging (MRI) readout. Knowledge of such lesions and their imaging appearances on MRI evaluation is essential for a reader. Additionally, a systematic approach is important to accurately diagnose these lesions. In this article we discuss the various causes of spinal sclerotic lesions, describe their MRI characteristics with relevant case examples, and outline a systematic approach to their evaluation.

The role of MRI in image-guided needle biopsy of focal bone and soft tissue neoplasms

Magnetic resonance imaging (MRI) plays a critical role in the management pathway of both soft tissue and bone neoplasms, from diagnosis through to post-treatment follow-up. There are a wide range of surgical, oncological, and combined treatment regimes but these rely on accurate histopathological diagnosis. This article reviews the role of MRI in the planning of image-guided needle biopsy for suspected soft tissue and bone tumors.

The SAPHO syndrome

OBJECTIVE

To review the epidemiology, presentation, diagnosis, treatment, pathogenesis, and genetics of the syndrome known under the acronym of SAPHO for Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis to heighten awareness of this entity.

METHODS

We conducted a Medline search using SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms as keywords and extracted further relevant articles from the retrieved references.

RESULTS

The SAHPO acronym identifies a syndrome encompassing a variety of osteoarticular disorders that are frequently accompanied by dermatoses characterized by neutrophilic pseudoabscesses, but can also occur in isolation. SAPHO syndrome is rare, although probably underrecognized because its diagnosis may be challenging because of the wide variability in its musculoskeletal and cutaneous manifestations. This is especially true when atypical sites are involved and when specific skin lesions are absent. There are no standardized treatment protocols available. Current treatments are empirical and have the objective of providing relief from the at times debilitating pain associated with SAPHO syndrome. They include nonsteroidal anti-inflammatory drugs and analgesics as first-line agents. Systemic corticosteroids, disease-modifying anti-rheumatic drugs, biologicals targeting tumor necrosis factor alpha and interleukin-1, and bisphosphonates have all been beneficial in some patients, but ineffective in others. This suggests that the pathogenesis of SAPHO syndrome is multifactorial, but this aspect remains poorly explored, although bacteria and immunological dysfunction are hypothesized to play a role.

CONCLUSIONS

The early recognition, diagnosis, and prompt treatment of SAPHO syndrome can prevent the unnecessary use of long-term antibiotics or invasive procedures, while rapidly alleviating pain in a majority of affected patients.

Diagnosing the SAPHO syndrome: a report of three cases and review of literature

SAPHO, an acronym for synovitis, acne, pustulosis, hyperostosis and osteitis, is a heterogeneous entity with myriad presentations and features overlapping with other entities. It is a differential in patients presenting with skin and bone symptoms, either singly or in combination. Often misdiagnosed radiologically as a malignancy or infection, the diagnosis is seldom thought of. We present three cases referred to us for evaluation of findings unrelated to the presenting symptoms. After evaluation, a (99)Tc bone scan was ordered, which showed the 'bull's head sign' in all the three cases, confirming the diagnosis. We review the literature for SAPHO. It has a few features which point to its diagnosis and can help us to distinguish it from other seronegative arthritis. The clinician should be aware of this entity and should not hesitate to order a (99)Tc bone scan. We conclude that SAPHO is not rare, but rather, it is underdiagnosed. High index of suspicion is necessary for diagnosis. A (99)Tc bone scan is diagnostic and should be ordered in patients having any of the presenting features of the syndrome. We put forward the suggestion of using (99)Tc bone scintigraphy to define a 'pre-MRI' stage of ankylosing spondylitis.

SAPHO syndrome

SAPHO syndrome is a disorder characterized by Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis. As the osteoarticular and skin manifestations often do not occur simultaneously and there are no validated diagnostic criteria, the diagnosis can be difficult. Clinical and imaging investigation is necessary to establish the many differential diagnoses of SAPHO syndrome. The etiopathogenesis involves infectious (probably Propionibacterium acnes), immunologic, and genetic factors. Treatment is based on information gathered from case reports and small series, and is related to specific skin or articular symptoms.

Friend or foe: high bone mineral density on routine bone density scanning, a review of causes and management

A finding of high BMD on routine DXA scanning is not infrequent and most commonly reflects degenerative disease. However, BMD increases may also arise secondary to a range of underlying disorders affecting the skeleton. Although low BMD increases fracture risk, the converse may not hold for high BMD, since elevated BMD may occur in conditions where fracture risk is increased, unaffected or reduced. Here we outline a classification for the causes of raised BMD, based on identification of focal or generalized BMD changes, and discuss an approach to guide appropriate investigation by clinicians after careful interpretation of DXA scan findings within the context of the clinical history. We will also review the mild skeletal dysplasia associated with the currently unexplained high bone mass phenotype and discuss recent advances in osteoporosis therapies arising from improved understanding of rare inherited high BMD disorders.

MRI of spinal bone marrow: part 2, T1-weighted imaging-based differential diagnosis

OBJECTIVE

The purpose of this article is to review the structure of bone marrow and the differential diagnosis of bone marrow pathology on the basis of T1-weighted MRI patterns.

CONCLUSION

Bone marrow is an organ that is evaluated routinely during MRI of the spine, particularly lumbar spine evaluation. Thus, it is one of the most commonly performed MRI examinations. T1-weighted MRI is a fundamental sequence in evaluating spinal marrow, and an understanding of T1-weighted MR signal abnormalities is important for the practicing radiologist.

SAPHO: What radiologists should know

SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) is an umbrella acronym for inflammatory clinical conditions whose common denominator is aseptic osteoarticular involvement with characteristic skin lesions. It involves all ages, can involve any skeletal site, and has variable imaging appearances depending on the stage/age of the lesion and imaging method. It mimics important differentials including infection and neoplasia. Awareness of the imaging features, especially in the spine, facilitates early diagnosis, prevents repeated biopsies, and avoids unnecessary surgery, while initiating appropriate treatment.