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.

Successful treatment of SAPHO syndrome (chronic nonbacterial osteomyelitis and acne) with anakinra and denosumab. Case report and review of therapy.

SAPHO is an acronym derived from capital letters of Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO). SAPHO syndrome is an umbrella term covering a constellation of bone lesions and skin manifestations. A 40-year-old male complained about his jaw and back pain, swelling of multiple joints and weight loss accompanied by physical deterioration and acne type skin lesions. Laboratory tests revealed abnormal elevation of inflammatory markers. Imaging studies illustrated multiple osteolytic bone lesions and paraosseal infiltrates. According to the set of criteria diagnosis of SAPHO syndrome was stated. The patient was treated with glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs), but only high dose dexamethasone and prednisone were effective. Daily subcutaneous administration of anakinra at the dose of 100 mg was initiated due to limited response to more classical therapies. Because of planned mandibular osteosynthesis initiation of denosumab was preferred before bisphosphonates. Therapeutic response was confirmed by FDG-PET/MR after 5 months of anakinra and denosumab therapy, showing decreased accumulation of FDG in periosteal and paraosseal infiltrates. Inflammatory markers significantly decreased, bone pain deferred but skin manifestation receded only partially. Therefore the response was evaluated as partial remission.

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.

Successful treatment of synovitis, acne, pustulosis, hyperostosis and osteitis syndrome with ixekizumab.

We report the use of ixekizumab in treating synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome, the first such report to our knowledge. The patient presented with palmoplantar pustulosis and sternoclavicular joint pain, which was markedly improved with ixekizumab treatment.

Does SAPHO syndrome exist in dermatology?

In the late 1960s, palmoplantar pustulosis (PPP) with sternocostoclavicular arthropathy was first described in Japan, predominantly affecting women in the perimenopausal age. In the 1970s, the chronic non-bacterial osteomyelitis and chronic recurrent multifocal osteomyelitis were initially observed in paediatric patients with approximately 70% girls. Acne fulminans accompanied by polyarthralgia have been observed since early 1970s, which almost exclusively occurs in adolescent boys. Report on spondyloarthropathy associated with hidradenitis suppurativa can be traced back to 1982. The SAPHO syndrome was coined in 1987 to lump together synovitis, acne, pustulosis, hyperostosis and osteitis to conceptualize a group of inflammatory osteocutaneous diseases of unclear etiopathogenesis and ill-defined associations spanning disparate age and gender groups. From historical view, Sasaki syndrome is proposed to replace SAPHO syndrome to represent PPP with sternocostoclavicular arthropathy in the absence of other skin manifestations. Hidradenitis suppurativa is folliculitis in pathogenesis and no longer classified as acne. PPP accompanied by psoriasis vulgaris is more likely psoriasis pustulosa palmoplantaris in dermatological aspect, and the associated arthritis is part of psoriatic arthropathy. Pathophysiology of these disorders is incompletely understood. To echo the advancement of high-throughput sequencing, splitting but not lumping of clinical findings would be a better strategy to decipher these multigenic complex inflammatory disorders.

Pharmacological Management of Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome Syndrome: A Proposal of a Treatment Algorithm.

ABSTRACT: Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare chronic disease with marked clinical and radiological heterogeneity. It is characterized by a combination of dermatological and osteoarticular manifestations. The treatment of SAPHO syndrome is not yet codified. It includes several therapeutic options such as anti-inflammatory drugs, bisphosphonates, antibiotics, conventional disease-modifying antirheumatic drugs, and biological treatment.This article aims to provide an updated review of the different pharmacological options for SAPHO syndrome. We also propose a therapeutic algorithm for the management of this disease.

SAPHO syndrome and pustulotic arthro-osteitis.

Synovitis-Acne-Pustulosis-Hyperostosis-Osteitis (SAPHO) syndrome is a rare inflammatory osteoarticular disorder, which encompassed many diseases, including pustulotic arthro-osteitis (PAO). Musculoskeletal manifestations, including osteitis, synovitis, and hyperostosis, are the hallmarks of the SAPHO syndrome and affect a variety of regions of the body. Recent survey indicated that more than 80% of cases of SAPHO syndrome in Japan were 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. Prevalence of SAPHO syndrome remains unavailable, whereas the prevalence of palmoplantar pustulosis (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 is seen in both groups. The diagnosis 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 of treatment seek to maximize health-related quality of life, preventing structural changes and destruction, and normalizing physical function and social participation. Finally, we review the non-pharmacological and pharmacological managements.

[SAPHO Syndrome Complicated with Ulcerative Colitis:Report of One Case].

Synovitis,acne,pustulosis,hyperostosis,and osteitis (SAPHO) syndrome is a rare disease. The previous literature demonstrated that about 10% of the patients with SAPHO syndrome were complicated with inflammatory bowel disease.So far,few cases of SAPHO syndrome complicated with inflammatory bowel disease have been reported in China.Herein,we reported a SAPHO syndrome case complicated with ulcerative colitis. The patient suffered from recurrent attacks of colitis following treatment of SAPHO syndrome with etanercept.

Serum Sp17 Autoantibody Serves as a Potential Specific Biomarker in Patients with SAPHO Syndrome.

SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome shows a wide variability in musculoskeletal and cutaneous manifestations, and it is therefore underrecognized and misdiagnosed in the clinic due to a lack of specific markers. In this study, we aimed to identify specific biomarkers by screening serum autoantibodies in SAPHO patients with a 17K human whole-proteome microarray. The serum anti-Sp17 autoantibody was identified and verified to be a specific biomarker in patients with SAPHO syndrome. Indeed, the level of the anti-Sp17 autoantibody was significantly increased in patients with active SAPHO compared to patients with an inactive disease and healthy controls (P < 0.05). Additionally, serum anti-Sp17 autoantibody levels correlated with those of serum hypersensitive C-reactive protein (hsCRP), the erythrocyte sedimentation rate (ESR), and ß-crosslaps (ß-CTx) in patients with active SAPHO disease. Moreover, anti-Sp17 autoantibody levels were markedly decreased after anti-inflammatory treatment with pamidronate disodium, which downregulated levels of hsCRP and ESR in patients with active SAPHO. Thus, serum levels of the anti-Sp17 autoantibody might serve as a specific biomarker for the diagnosis of SAPHO syndrome or for monitoring the disease status.

Abundance alteration of nondominant species in fecal-associated microbiome of patients with SAPHO syndrome.

BACKGROUND: SAPHO syndrome is a group of symptoms consisting of synovitis, acne, pustulosis, hyperostosis and osteosis. There is no specific laboratory index assist in the diagnosis of SAPHO because of its highly heterogeneous clinical manifestations. Pathogenic microorganisms had been identified in biopsies of some SAPHO cases and particular gene mutations were also linked to the occurrence of SAPHO. It is largely unknown whether intestinal microbiome plays a role in pathogenesis of SAPHO. To explore the intestinal microbiome structure of SAPHO syndrome, fecal samples from 17 SAPHO patients and 14 healthy controls (HC) were collected for 16S rDNA sequencing. RESULTS: Our results showed that there was no significant difference in alpha indexes and beta diversity between SAPHO and HC samples, while there were 14 operational taxonomic units (OTUs) in the Wilcoxon rank-sum test and 42 OTUs in the MetagenomeSeq analysis showed significant difference in distribution between the SAPHO and HC groups, 3 of which in Firmicutes were also observed in the random forest analysis and used to construct a receiver operating characteristic curve to evaluate the diagnostic value, the area under the curve was 0.86. CONCLUSION: Fecal-associated microbiome in the SAPHO samples was characterized by the alteration in abundance of some nondominant species, and the 3 selected OTUs in Firmicutes could serve as candidate biomarkers for SAPHO syndrome diagnosis.

Disease activity in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome: the utility of the SPARCC MRI scoring system for assessment of axial spine involvement.

OBJECTIVES: The aim of this study is to investigate the relationship between spinal MRI findings with disease activity and other clinical and serological parameters, and to determine the importance of MRI scoring system in evaluating disease activity of SAPHO syndrome. METHODS: Thirty patients with SAPHO syndrome underwent clinical, laboratory and MRI evaluation at baseline, 3 months, 6 months and 1 year. Magnetic resonance images were analysed using modified Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. Correlations between MRI score and clinical and laboratory parameters were analysed using Spearman's rank correlation test. RESULTS: Persistent improvement was observed after 12 months in terms of total modified SPARCC scores (37(12,59) vs. 23(5,45) at baseline and 12 months, p<0.05). Total modified SPARCC scores showed Spearman correlations with hypersensitive C-reaction protein (hs-CRP), ankylosing spondylitis disease activity score (ASDAS) and bath ankylosing spondylitis metroloty index (BASMI) at baseline, 3 months, 6 months and 12 months (p varied from <0.001 to <0.05, and r varied from 0.418 to 0.601). Modified SPARCC scores of spine joint, as the largest contribution to the total scores with the mean score of 12(5,30) after 12 months vs. 26 (12,40) at baseline. CONCLUSIONS: The modified SPARCC score proposed in this study exhibits promising potential in the evaluation of extensive radiographic damage in SAPHO and the reflection the disease activity. Our study suggests that MRI could be used together with other parameters of disease activity in the assessment of symptomatic SAPHO patients with spine involvement.

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.

Metastatic Carcinoma of Prostate as a Mimicker of SAPHO Syndrome.

Paraneoplastic arthritides are a group of immune-mediated inflammatory arthropathies associated with occult or manifest malignancy. Musculoskeletal spread of an underlying malignancy may also mimic many rheumatologic conditions. Distinguishing primary rheumatologic condition from paraneoplastic arthritides versus direct musculoskeletal spread of malignancy can be challenging especially in individuals with prior history of cancer and new musculoskeletal complaints. SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome is an uncommon, although under recognized autoimmune disorder. Two musculoskeletal manifestations, namely inflammatory osteitis and hyperostosis of anterior chest wall with or without dermatologic manifestations, constitute a unifying feature of SAPHO syndrome. However, diagnosis of SAPHO syndrome is one of exclusion, and a wide variety of disorders including infections, malignancy (chondrosarcoma/osteosarcoma/metastasis), metabolic bone disorders (Paget's disease), osteoarthritis, seronegative spondyloarthropathy (spA) and osteonecrosis form part of a broad differential diagnosis. We present the case of a man, aged 72 years, with signs and symptoms of SAPHO syndrome and skin findings. Detailed history, radiological imaging, dermatology appearance, and role of immunohistochemical markers, especially staining for NKX3.1 protein with a novel antibody, led to a diagnosis of metastatic prostate adenocarcinoma. To our knowledge, this is the first case of metastatic adenocarcinoma of the prostate manifesting as SAPHO syndrome and cutaneous metastasis.

Hypertrophic Pachymeningitis Related Brain Infarction in Synovitis-Acne-Pustulosis-Hyperostosis Osteomyelitis Syndrome.

A 50-year-old woman with a history of synovitis-acne-pustulosis-hyperostosis osteomyelitis (SAPHO) syndrome was admitted for left unilateral neglect, dysarthria, and left hemiparesis. Brain MRI showed multiple infarctions in the territory of the right middle cerebral artery and gadolinium enhancement of the thickened frontotemporal dura mater on the right side. MR angiography showed significant narrowing of the cavernous segment of the right internal carotid artery. The right internal carotid artery stenosis was thought to originate from hypertrophic pachymeningitis associated with SAPHO syndrome. This is the first report of brain infarction due to internal carotid artery stenosis caused by hypertrophic pachymeningitis associated with SAPHO syndrome.

[SAPHO syndrome : An overview and nosological differentiation of 35 disease cases]. / SAPHO-Syndrom : Ein Überblick und nosologische Differenzierung von 35 Krankheitsfällen.

The SAPHO syndrome is not a single entity but an inhomogeneous, nosologically heterogeneous complex of symptoms with unknown etiology and heterogeneous pathogenesis. Clinically subacute, recurrent or chronic disease processes and a common skin-bone association (skibo disease) can be found. Under the acronym SAPHO, chronically recurrent multifocal osteomyelitis (CRMO) is the most common disease that can occur in youth as well as adolescence. Spondylarthritis hyperostotica pustulo-psoriatica with the triad palmoplantar pustulosis, sternoclavicular hyperostosis and ossifying spinal manifestations is the most common SAPHO form found in adults. Abortive disease forms are the inflammatory anterior chest wall syndrome, extended sternoclavicular hyperostosis syndrome of the clavicle bone, acne CRMO and acne spondylarthritis. The SAPHO disease usually heals with a relatively favorable prognosis but there are also unfavorable courses with functional limitations. The diagnosis should be made based on clinical examination, imaging (x-ray, scintigraphy, magnetic resonance imaging) and/or histological bone biopsy analysis. Treatment should be interdisciplinary. Antibiotic treatment is obsolete. This article provides an overview of the SAPHO syndrome and a clinical-rheumatological imaging differentiation as well as classification of 35 cases at first presentation.

Pustular Psoriasis and Associated Musculoskeletal Disorders.

Pustular psoriasis (PsO) is an uncommon variant of PsO that may present in a generalized or localized fashion with or without musculoskeletal or systemic inflammatory involvement.Generalized pustular PsO (GPP) presents as a widespread acute or subacute pustular eruption that may be familial and is often associated with severe flares and systemic inflammation. The palmoplantar pustulosis variant is localized to palms and soles, whereas acrodermatitis continua of Hallopeau is localized to the nail apparatus. Patients with pustular PsO may have overlapping plaque PsO and may develop psoriatic arthritis (PsA). Pustulosis is also a feature of both synovitis, acne, pustulosis, hyperostosis, osteomyelitis (SAPHO) syndrome and chronic non-bacterial osteomyelitis. At the 2020 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) annual meeting, members were given an overview of the cutaneous features of pustular PsO, SAPHO, and recent insights into the genetics of GPP, leading to new targeted drug therapies and the development of validated endpoints.

Genetic variants in FBLIM1 gene do not contribute to SAPHO syndrome and chronic recurrent multifocal osteomyelitis in typical patient groups.

BACKGROUND: Syndrome of synovitis acne pustulosis hyperostosis osteitis (SAPHO) and chronic recurrent multifocal osteomyelitis (CRMO) present two diseases of a dermatologic and rheumatologic spectrum that are variable in manifestation und therapeutic response. Genetic risk factors have long been assumed in both diseases, but no single reliable factor has been identified yet. Therefore, we aimed to clinically characterize a patient group with syndrome of synovitis acne pustulosis hyperostosis osteitis (SAPHO) (n = 47) and chronic recurrent multifocal osteomyelitis (CRMO)/ chronic non-bacterial osteomyelitis (CNO) (n = 9) and analyze a CRMO candidate gene. METHODS: Clinical data of all patients were collected and assessed for different combinations of clinical symptoms. SAPHO patients were grouped into categories according to the acronym; disease-contribution by pathogens was evaluated. We sequenced coding exons of FBLIM1. RESULTS: Palmoplantar pustular psoriasis (PPP) was the most common skin manifestation in CRMO/CNO and SAPHO patients; most SAPHO patients had sterno-costo-clavicular hyperostosis. The most common clinical category of the acronym was S_PHO (n = 26). Lack of pathogen detection from bone biopsies was more common than microbial isolation. We did not identify autosomal-recessive FBLIM1 variants. CONCLUSIONS: S_PHO is the most common combination of symptoms of its acronym. Genetic analyses of FBLIM1 did not provide evidence that this gene is relevant in our patient group. Our study indicates the need to elucidate SAPHO's and CRMO/CNO's pathogenesis.

Serum IgG4 elevation in SAPHO syndrome: does it unmask a disease activity marker?

OBJECTIVES: SAPHO syndrome is a rare inflammatory disorder with multiple phenotypes, including synovitis, acne, pustulosis, hyperostosis, and osteitis. IgG4 is a subclass of immunoglobulin G, and the elevation of IgG4 has been found in different autoimmune diseases. In the present study, we explored the clinical significance of serum IgG4 levels in patients with SAPHO syndrome. METHODS: Fifty-two patients who met the classification criteria of SAPHO syndrome were included in this study. Clinical data and disease activity markers were collected including erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hsCRP), pain visual analogue scale (VAS), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Ankylosing Spondylitis Disease Activity Score (ASDAS). Serum immunoglobin (IgA, IgM, and IgG) and IgG subclass (IgG1, IgG2, IgG3, and IgG4) levels were determined using the immunonephelometric assay. RESULTS: Raised serum IgG4 levels (>1400 mg/dL) were detected in 23% (12/52) of patients. Patients with elevated sIgG4 levels had significantly higher pain VAS (5.42±2.76 vs. 3.08±1.78, p=0.02), BASMI (1.80±1.64 vs. 0.38±0.94, p=0.03) and ASDAS (3.20±0.65 vs. 1.74±0.58, p<0.001) levels compared with patients with normal sIgG4 levels. This difference was also observed for ESR (38.2 vs. 22.2 mm/h, p=0.01) and serum CRP (21.0 vs. 2.2 mg/L, p=0.04) levels, which also positively correlated with sIgG4 levels. We also included 4 patients whose IgG4 levels decreased and correlated with the decrease in hsCRP and ESR levels after treatment. CONCLUSIONS: Elevated sIgG4 levels are common in patients with SAPHO syndrome and are associated with high disease activity. Further investigations are needed for this phenomenon.

New Insights into Adult and Paediatric Chronic Non-bacterial Osteomyelitis CNO.

PURPOSE OF REVIEW: To describe in detail the clinical synopsis and pathophysiology of chronic non-bacterial osteomyelitis and SAPHO syndrome. RECENT FINDINGS: Chronic non-bacterial osteomyelitis (CNO) has been identified as a disease entity for almost 50 years. This inflammatory bone disorder is characterized by osteolytic as well as hyperostotic/osteosclerotic lesions. It is chronic in nature, but it can present with episodic flairs and phases of remission, which have led to the denomination "chronic recurrent osteomyelitis", with its severe multifocal form "chronic recurrent multifocal osteomyelitis" (CRMO). For almost three decades, an infectious aetiology had been considered, since especially Propionibacterium acnes had been isolated from bone lesions of individual patients. However, this concept has been challenged since long-term antibiotic therapy did not alter the course of disease and modern microbiological techniques (including PCR) failed to confirm bone infection as an underlying cause. Over recent years, a profound dysregulation of cytokine expression profiles has been demonstrated in innate immune cells of CNO patients. A hallmark of monocytes from CNO patients is the failure to produce immune regulatory cytokines interleukin-10 (IL-10) and IL-19, which have been linked with genetic and epigenetic alterations. Subsequently, a significant upregulation of pro-inflammatory, NLRP3 inflammasome-dependent cytokines (IL-1ß and TNF-α), has been demonstrated. The current knowledge on CNO, the underlying molecular pathophysiology, and modern imaging strategies are summarized; differential diagnoses, treatment options, outcome measures, as well as quality of life studies are discussed.

Biologic Therapy for Hidradenitis Suppurativa Plus Conglobate Acne Associated with SAPHO Syndrome: A Case Report.

is missing (Short Communication).