A case of SAPHO (synovitis-acne-pustulosis-hyperostosis-osteomyelitis) syndrome in which [18F]fluorodeoxyglucose positron emission tomography was useful for differentiating from multiple metastatic bone tumors

Synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome: review and update

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a spectrum of heterogeneous diseases characterized by osteoarticular and dermatological manifestations. Osteitis and hyperostosis are core clinical manifestations in SAPHO syndrome, typically affecting multiple areas and possibly progressing to irreversible osteoarticular damage. Most patients with SAPHO have cutaneous involvement, mainly manifested as palmoplantar pustulosis and severe acne. Systemic manifestations are uncommon but occasionally reported. Epidemiological studies suggest the annual prevalence of SAPHO syndrome varies from 0.00144 in 100,000 in Japanese individuals to fewer than 1 in 10,000 in White individuals. The precise etiopathogenesis of SAPHO remains unclear, but it is generally considered an autoinflammatory syndrome that may be related to various etiologies, such as immune dysfunction, infection and genetic predisposition. Owing to the relapsing-remitting disease course, the goal of management is to improve clinical symptoms and prevent disease progression. Various treatments, including nonsteroidal anti-inflammatory drugs, conventional disease-modifying antirheumatic drugs, bisphosphonates, biologics, and antibiotics, are promising options for alleviating the disease.

F-18 FDG PET/CT in 26 patients with SAPHO syndrome: a new vision of clinical and bone scintigraphy correlation

Backgrounds

Whole-body bone scintigraphy (WBBS) and MRI are widely used in assessment of patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. However, the value of F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in SAPHO syndrome was unclear. The aim of this study was to characterize the manifestation of SAPHO syndrome on ¹⁸F-FDG PET/CT and explore its relationship with clinical symptoms and WBBS.

Methods

Twenty-six patients who suffered from SAPHO syndrome and had undergone whole-body ¹⁸F-FDG PET/CT were recruited in Peking Union Medical College Hospital from 2004 to 2016. Clinical manifestations and laboratory findings were recorded for all patients. Imaging data on 18F-FDG PET/CT and WBBS were collected and analyzed retrospectively.

Results

All the 26 patients (20 females and 6 males) exhibited skeletal abnormalities on ¹⁸F-FDG PET/CT. Multiple skeletal lesions affecting the anterior chest wall or spine with low to moderate ¹⁸F-FDG uptake and coexistence of osteolysis and osteosclerosis presented as the typical features of SAPHO syndrome. Sixteen (61.5%) patients had abnormal ¹⁸F-FDG uptake outside the osteoarticular system. PET scan had moderate to substantial agreement with CT and WBBS in revealing lesions in the anterior chest wall and axial skeleton. Nonetheless, the correlation between increased ¹⁸F-FDG uptake and clinical symptoms was weak.

Conclusions

SAPHO syndrome exhibits characteristic features on ¹⁸F-FDG PET/CT. It showed comparable capacity in revealing skeletal lesions with bone scintigraphy.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0795-0) contains supplementary material, which is available to authorized users.

Clinical features and radiological findings of 67 patients with SAPHO syndrome

OBJECTIVES

The purpose of this study was to facilitate the understanding of the SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis) syndrome by analyzing the clinical and radiological features of 67 Japanese patients with SAPHO syndrome.

METHODS

Sixty-seven Japanese patients (female/male: 44/23, mean age at onset: 48.5 years) were diagnosed with SAPHO syndrome from 2002 to 2013 at our hospital. Medical records and radiological imaging of these patients were retrospectively reviewed.

RESULTS

Among the 67 patients, 41 had dermatological manifestations, such as palmoplantar pustulosis, acne, and psoriasis. Initial symptom was local pain in all patients, and the most common initial site of the symptom was the anterior chest. Bacterial and fungal cultures from 20 bone biopsies were all negative. Histopathological diagnosis of the specimens was non-specific inflammation in all cases. Bone lesions were observed in 65 patients (97.0%). On the other hand, articular lesions including enthesitis were found in 31 patients (46.2%).

CONCLUSION

SAPHO syndrome had different clinical and radiological aspects. The clinical features were not remarkable, except the dermatological manifestations and the involvement of the anterior chest. Bone lesions including hyperostosis and osteitis were found radiographically in the majority of patients with SAPHO syndrome. These are the characteristics of the SAPHO syndrome, with the exclusion of other bone diseases.

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.

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.

A case of SAPHO syndrome with destructive spondylodiscitis suspicious of tuberculous spondylitis

We report a rare case of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome in which the differential diagnosis included tuberculous spondylitis and the patient ultimately required reconstructive spinal surgery. The patient was a 60-year-old woman who presented with severe low-back and leg pain after treatment for tuberculosis. Roentgenography and magnetic resonance imaging of the lumbar spine revealed destructive changes suggestive of tuberculous spondylitis. [(18)F]-fluoro-2-deoxyglucose positron emission tomography/computed tomography showed uptake in the cervical spines, lumbar spines, and sacroiliac joints from which she was suspected of having SAPHO syndrome without skin manifestations. However, as her symptoms did not respond to conservative treatment, we performed reconstructive surgery of the lumbar spine. Spinal specimens obtained surgically showed nonspecific inflammation and fibrous hypertrophy of the bone marrow, confirming a diagnosis of the SAPHO syndrome. Her symptoms improved markedly after surgery, although she required occasional prednisolone for moderate polyarthralgia and leg pain.

SAPHO syndrome with rapidly progressing destructive spondylitis: two cases treated surgically

The authors present two cases of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome with rapidly progressing destructive spondylitis treated surgically. The spinal lesions in SAPHO syndrome generally have a good prognosis and rarely cause the structural destruction or neurological deterioration. Case 1: a 63-year-old female had palmoplantar pustulosis for 2 years. At first, she only felt a pain in the nape with no inducing factor. Two months later, she had incomplete quadriplegia (ASIA scale C). Magnetic resonance imaging showed destruction of C4-C7, kyphotic deformity, and severe compression of the spinal cord. Decompression and reconstruction surgery using anterior and posterior approach improved her paralysis. Case 2: a 69-year-old female complained of persistent back pain. Magnetic resonance imaging revealed spondylitis of T7-T9. Although there were no typical skin lesions, we diagnosed SAPHO syndrome by hyperostosis of the sternocostoclavicular joint and sacral joint. Destruction with kyphotic deformity of the spine progressed gradually for 3 months. Curettage and reconstruction surgery using thoracic endoscope relieved her pain and prevented the destruction of the spine. The histopathology of the specimen obtained surgically showed non-specific inflammation in both cases. Spondylitis in SAPHO syndrome may cause severe destruction and kyphotic deformity followed by paralysis.