Radiological features of long bones in synovitis, acne, pustulosis, hyperostosis, osteitis syndrome and their correlation with pathological findings

SAPHO syndrome: current clinical, diagnostic and treatment approaches

This review provides an overview of SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis), a rare autoinflammatory disease that primarily affects bones, skin, and joints. We conducted a search on Medline/PubMed using keywords such as SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms. SAPHO syndrome is rare, with a reported frequency of 1 in 10,000 in the Caucasian population. However, the actual incidence of SAPHO syndrome is unknown, and the incidence of the disease is likely higher. The pathogenesis of SAPHO syndrome remains incompletely understood. Current evidence suggests that SAPHO results from a complex interplay between immune dysregulation, genetic susceptibility, and environmental factors. It's not clear if SAPHO syndrome is an autoimmune disease or an autoinflammatory disease, but current evidence suggests that it's more likely an autoinflammatory disease because of things like neutrophil hyperactivity, fewer natural killer (NK) cells, high levels of interleukin (IL)-1, and a good response to treatments that block IL-1. Osteo-articular (OA) involvement is a key clinical feature of SAPHO. It affects the anterior chest wall, axial skeleton, peripheral joints, mandible, long bones of the extremities, and pelvis. Dermatological involvement is a common target in SAPHO, with lesions observed in 60-90% of cases. Common skin lesions include psoriasis and acne, with hidradenitis suppurativa and neutrophilic dermatoses being less commonly seen. Other clinical findings include constitutional symptoms caused by systemic inflammation, such as fever, weight loss, and fatigue. There is no specific laboratory finding for SAPHO syndrome. However, during active disease, there may be an increase in positive acute phase markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement levels, mild leukocytosis, and thrombocytosis. Diagnosis is crucial for SAPHO syndrome, which lacks a specific diagnostic finding and is often underrecognized. A comprehensive evaluation of a patient's medical history and physical examination is crucial. Treatment options include non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, conventional and synthetic disease-modifying agents (cDMARDs and sDMARDs), biological therapies, bisphosphonates, and antibiotics. Biological treatments have emerged as a viable alternative for SAPHO patients who do not respond to conventional treatments.

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome of femoral neoplasm-like onset: a case-based review

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is an umbrella term covering a constellation of bone lesions and skin manifestations, but has rarely been clarified in the clinic. We report a 28-year-old woman who had initial onset of SAPHO syndrome with involvement of the femur, and she experienced a tortuous diagnostic course. We also performed a literature review of SAPHO syndrome cases involving the femur and summarize several empirical conclusions by integrating previous findings with our case. Furthermore, we propose our perspective that ailment of the skin caused by infection of pathogens might be the first hit for triggering or perpetuating the activation of the immune system. As a result, musculoskeletal manifestations are probably the second hit by crosstalk of an autoimmune reaction. The skin manifestations preceding bone lesions can be well explained. Current interventions for SAPHO syndrome remain controversial, but drugs aiming at symptom relief could serve as the first preference for treatment. An accurate diagnosis and appropriate treatment can cure patients in a timely manner. Although the pathogenesis of SAPHO syndrome remains to be determined, physicians and surgeons still need to heighten awareness of this entity to avoid invasive procedures, such as frequent biopsies or nonessential ostectomy.

Bone histomorphometric and immunohistological analysis for hyperostosis in a patient with SAPHO syndrome: A case report

A 56-year-old Japanese woman with a history of palmoplantar pustulosis was admitted for examination due to left femur pain. Radiography and computed tomography showed thickening of the bone on the outer portion of the left femur. Bone scintigraphy of the left femur showed intense radioactive uptake. Consequently, the patient was diagnosed with SAPHO syndrome. Bone histomorphometric analysis of the left femur showed cancellous bone with thickened cortical bone. Whilst normal bone shows cancellous bone with double labeling (normal turn over), and cortical bone with no labeling (low turn over, adynamic state), this case presented with both cancellous and cortical bone with marked double labeling (indicating high turn over), abundant osteoid and woven bone. Immunohistological analysis showed that cells lining the bone surface consisted of osteoblasts and were positive for alkaline phosphatase (ALP). Few to little of these cells were positive for tartrate-resistant acid phosphatase (TRAP)-5B, cathepsin K and matrix metallopeptidase 9 (MMP-9). These results indicate that, in this case study, excessive production of osteoblasts contributed to hyperostosis of the left femur, with abundant osteoid and woven bone. This type of bone formation in SAPHO syndrome is not lamellar bone seen in normal bone, but rather fragile and mechanically weak bone, resulting in bone pain. Doxycycline may be a therapeutic option for bone pain in this patient.

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.

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.

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.

Mucosal lesions may be a minor complication of SAPHO syndrome: a study of 11 Japanese patients with SAPHO syndrome

Since the term synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome was proposed by Chamot et al. (Rev Rhum Mal Osteoartic 54:187-196, 1987), clinical reviews concerning this syndrome have been mainly reported from Europe. We carried out a retrospective analysis of 11 Japanese patients with SAPHO syndrome, and reviewed the clinical features of our series in comparison with those in a European large case study. In this study the major features of SAPHO syndrome were chronic osteitis of the anterior chest wall and pustulotic arthro-ostitis with middle age onset, and mucosal lesions seemed to be a minor complication of SAPHO syndrome. The non-erosive peripheral large joints arthritis and the particular HLA types (HLA-B51, B52, or A26), which had been reported to be increased in Behcet's disease, were frequently seen in SAPHO syndrome with mucosal lesions. This study also suggests that SAPHO syndrome with mucosal lesions may be part of a broader disease spectrum including Behcet's disease.

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

We report the case of a 50-year-old Japanese woman with SAPHO (synovitis-acne-pustulosis-hyperostosis-osteomyelitis) syndrome. Radiographs showed osteosclerosis of the cervical and lumbar vertebrae, as well as osteosclerosis and osteolysis of the right femoral neck, resembling multiple metastatic bony lesions. Arriving at a diagnosis required hematological and imaging tests. Whole-body bone scintigraphy identified diffuse uptake from the lower cervical vertebrae to the lumbar vertebrae and marked uptake in the right femoral neck. However, with [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) scanning, abnormal [(18)F]FDG uptake was not detected in cervical and lumbar spine, or in the femoral neck. Bone biopsy showed signs of chronic nonspecific inflammation, rather than tumor or infection. Based on these findings, the patient was diagnosed with SAPHO syndrome unaccompanied by skin lesions, and administration of non-steroidal anti-inflammatory drugs provided pain relief.