[Differential diagnosis of chronic synovitis]

[Localized tenosynovial giant cell tumor : Results from the Histopathological Arthritis Register of the German Society for Orthopedic Rheumatology]

BACKGROUND

The tenosynovial giant cell tumor (pigmented villonodular synovitis) is a proliferative, mainly benign soft tissue tumor of the tendon sheaths, bursae and joints arising from the synovia. It can be divided into circumscribed localized and destructive diffuse types. Approximately 1% of all joint diseases are due to this entity. The tumor is considered as a rarity. Mostly case studies exist. For this study the focus was set on the localized type (L-TSRZT), which accounts for 90% of the diagnoses of this tumor. Given its rarity, data are limited. Therefore, the research aim was to provide data on prevalence, primary location and sensitivity of clinical versus histopathological diagnosis in a German sample.

METHODS

Based on the Histopathological Arthritis Register of the German Society for Orthopedic Rheumatology, the data of the L‑TSRZT were retrospectively analyzed (time frame 1 January 2018-28 December 2020).

RESULTS

This database contained N = 7595 cases of arthropathy. A total of n = 45 patients with the diagnosis L‑TSRZT were identified. The prevalence of the tumor was 0.6%, 95% CI [0.4%, 0.8%], or 5.9 cases per 1000. The primary location involved the finger (48.9%). In 14 of 45 cases the diagnosis was correctly determined from the clinical side, corresponding to a sensitivity of 31.1%, 95% CI [18.2%, 46.7%].

CONCLUSION

For the first time, this paper was able to provide data on a large sample for Germany. Notably, the low sensitivity of the clinical diagnosis confirms the importance of histopathology for diagnosing L‑TSRZT.

Research on the inhibition for aseptic loosening of artificial joints by Sr-doped calcium polyphosphate (SCPP)in vivo

Aseptic loosening of artificial joints is the most common complication after artificial joint replacement. Finding the solution to tackle aseptic loosening of artificial joints is a focus in bone and joint surgery research field.In vitrostudies of Sr-doped calcium polyphosphate (SCPP) have found by our team that it could promote osteoblast proliferation and inhibit osteoclast activity, and it has a potential inhibitory effect on aseptic loosening by suppressing the expression of receptor activator of nuclear factor-κ B ligand and improving the expression of OPG. The present study aims to confirm the conclusionin vitroby the mean of animal experiment. The Ti rod prosthesis coated with SCPP, calcium polyphosphate (CPP), and Ultra-high molecular weight polyethylene (UHMWPE were implanted in the femur (the internal surface of bone tunnel was also coated with SCPP, CPP and UHMWPE respectively). Radiography (x-rays, micro-CT), histochemistry (Hematoxylin-eosin staining (HE), methylene blue-acid fuchsin, Von Kossa histological staining), molecular biology (alkaline phosphatase and TRAP5b factors, Mir21-5p and Mir 26a-5p) were performed to analyzed the effects of SCPP within 20 weeks. The Radiography results showed that osteolysis with various severity occurred in all groups, and SCPP group had the mildest osteolysis. Histochemistry results showed that arthritis was milder in SCPP and CPP groups, while the bone formation in SCPP group was most significant. Its bone reconstruction effect was the best as well. The Molecular biology results showed that the bone reconstruction was out-sync in each group. Compared with other groups, the bone resorption occurred at the latest and the bone resorption time was the shortest in experimental animals of SCPP group. All results indicated that SCPP could promote osteoblast activity and bone reconstruction, improve the integration of bone interface between prosthesis and base bone, reduce osteoclast activity and shorten the osteoclast action time at the implantation sitein vivo. Thus, it could postpone or alleviate the occurrence and development of aseptic looseningin vivo. Therefore, SCPP could be a promising material for the construction of artificial joints with the ability to resist aseptic loosening.

[Histopathological classification principles of rheumatic joint diseases : Contribution of pathology to the diagnosis]

Even though the diagnostics of rheumatic joint diseases are mostly based on clinical, immunoserological and imaging criteria, histopathology can also make a significant contribution. This is particularly true for clinically unclear monoarticular and periarticular diseases. The contribution of histopathology to the diagnosis of rheumatic diseases is manifold since the histopathological differential diagnosis includes the complete spectrum of synovial diseases. This heterogeneous pathogenetic spectrum is described in the joint pathology algorithm, which includes inflammatory and non-inflammatory diseases. To the latter group belong certain benign tumors such as the diffuse variant of the tenosynovial giant cell tumor, lipoma, hemangioma, vascular malformations and synovial chondromatosis. Additionally, the rare group of storage diseases should be kept in mind. Inflammatory diseases can be discriminated into crystal-induced arthropathies mainly such as gout and pseudogout, into granulomatous diseases such as tuberculosis and foreign-body inoculations, and finally into the large group of non-granulomatous, non-infectious synovitis. This large group is by far the most common, and it often causes difficulties in assigning the histopathological findings to a concrete rheumatologic diagnosis. In this context the synovitis score should be applied as a diagnostic device in these cases, leading to the diagnosis of a low-grade synovitis (which is associated with degenerative arthropathies) or of a high-grade synovitis (associated with rheumatic diseases). Identification of crystals and crystal-like deposits should be carried out with the application of the joint particle algorithm which addresses the identification of endogenous and non-endogenous particle deposits in the synovial tissues. Additionally, the synovitis-score may be used for evaluation of arthritis-progresssion and for the evaluation of inflammation-regression as a consequence of therapy with biologicals.

[Arthur Vick Prize 2017 of the German Society of Orthopaedic Rheumatology]

The German Society of Orthopaedic Rheumatology (DGORh) honored Prof. Dr. med. Veit Krenn (MVZ-ZHZMD-Trier) with the Arthur Vick Prize 2017. With this award, scientific results with high impact on the diagnosis, therapy and pathogenetic understanding of rheumatic diseases are honored. In cooperation with pathologists and colleagues from various clinical disciplines Prof. Dr. med. Veit Krenn developed several histopathologic scoring systems which contribute to the diagnosis and pathogenetic understanding of degenerative and rheumatic diseases. These scores include the synovitis score, the meniscal degeneration score, the classification of periprosthetic tissues (SLIM classification), the arthrofibrosis score, the particle score and the CD15 focus score. Of highest relevance for orthopedic rheumatology is the synovitis score which is a semiquantitative score for evaluating immunological and inflammatory changes of synovitis in a graded manner. Based on this score, it is possible to divide results into low-grade synovitis and high-grade synovitis: a synovitis score of 1-4 is called low-grade synovitis and occurs for example in association with osteoarthritis (OA), post-trauma, with meniscal lesions and hemochromatosis. A synovitis score of 5-9 is called high-grade synovitis, e.g. rheumatoid arthritis, psoriatic arthritis, Lyme arthritis, postinfection and reactive arthritis as well as peripheral arthritis with Bechterew's disease (sensitivity 61.7%, specificity 96.1%). The first publication (2002) and an associated subsequent publication (2006) of the synovitis score has led to national and international acceptance of this score as the standard for histopathological assessment of synovitis. The synovitis score provides a diagnostic, standardized and reproducible histopathological evaluation method for joint diseases, particularly when this score is applied in the context with the joint pathology algorithm.

15 years of the histopathological synovitis score, further development and review: A diagnostic score for rheumatology and orthopaedics

The histopathological synovitis score evaluates the immunological and inflammatory changes of synovitis in a graduated manner generally customary for diagnostic histopathological scores. The score results from semiquantitative evaluation of the width of the synovial surface cell layer, the cell density of the stroma and the density of the inflammatory infiltration into 4 semiquantitative levels (normal 0, mild 1, moderate 2, severe 3). The addition of these values results in a final score of 0-9 out of 9. On the basis of this summation the condition is divided into low-grade synovitis and high-grade synovitis: A synovitis score of 1 to≤4 is called low-grade synovitis (arthrosis-associated/OA synovitis, posttraumatic synovitis, meniscopathy-associated synovitis and synovitis with haemochromatosis). A synovitis score of≥5 to 9 is called high-grade synovitis (rheumatoid arthritis, psoriatic arthritis, Lyme arthritis, postinfection/reactive arthritis and peripheral arthritis with Bechterew's disease). By means of the synovitis score it is therefore possible to distinguish between degenerative/posttraumatic diseases (low-grade synovitis) and inflammatory rheumatic diseases (high-grade synovitis) with a sensitivity of 61.7% and a specificity of 96.1%. The diagnostic accuracy according to ROC analysis (AUC: 0.8-0.9) is good. Since the first publication (2002) and an associated subsequent publication (2006), the synovitis score has nationally and internationally been accepted for histopathological assessment of the synovitis. In a PubMed data analysis (status: 14.02.2017), the following citation rates according to Cited by PubMed Central articles resulted for the two synovitis score publications: For DOI: 10.1078/0344-0338-5710261 there were 29 Cited by PubMed Central articles and for the second extended publication DOI:10.1111/j.1365-2559.2006.02508 there were 44 Cited by PubMed Central articles. Therefore a total of 73 PubMed citations are observed over a period of 15 years, which demonstrates an international acceptance of the score. This synovitis score provides for the first time a diagnostic, standardised and reproducible histopathological evaluation method enabling a contribution to the differential diagnosis of chronic inflammatory general joint diseases. This is particularly the case by incorporation into the joint pathology algorithm. To specify the synovitis score an immunohistochemical determination of various inflammation-relevant CD antigens is proposed to enable a risk stratification of high-grade synovitis (e.g.: progression risk and sensitivity for biologicals).

[Pigmented villonodular synovitis. A rare differential diagnosis of synovial joint swelling]

BACKGROUND

Pigmented villonodular synovitis (PVNS) describes a rare disease caused by an abnormal proliferation of the synovial membrane in large and small joints. In order to achieve an optimal result of treatment it is necessary to carry out specific diagnostics and a targeted therapy approach.

OBJECTIVE

This article gives a review of the epidemiology, etiopathogenesis and diagnostic management of PVNS as well as presenting the current therapy and treatment recommendations.

MATERIAL AND METHODS

A systematic search of the literature was performed in the databank of the National Center for Biotechnology Information ( http://www.ncbi.nlm.nih.gov/pubmed ). The search targeted randomized clinical and experimental studies, systematic and non-systematic review articles, expert opinions and case reports related to PVNS, independent of the level of evidence attained by each study.

RESULTS

The differential diagnosis of PVNS should be considered in cases of recurrent hemorrhagic joint effusions. The cause of the disease has not yet been exactly clarified. The final diagnosis can ultimately only be confirmed by histological investigations. In order to obtain representative histological tissue samples for the diagnosis, magnetic resonance imaging (MRI) with the appropriate heme sequences should be carried out prior to taking samples. The management of PVNS is often difficult due to the high risk of recurrence depending on the various forms. In view of the high rate of recurrence, therapy should include a complete synovectomy.

CONCLUSION

For the surgical approach arthroscopic and open procedures have been described, which are currently controversially discussed with respect to the complication and recurrence rates. Adjuvant interventional therapy forms, such as radiosynoviorthesis are recommended to reduce the recurrence rate.

[Histopathological particle algorithm. Particle identification in the synovia and the SLIM]

BACKGROUND

In the histopathological diagnostics of synovitis and the synovium-like interface membrane (SLIM) the identification of crystals and crystal-like deposits and the associated inflammatory reactions play an important role. The multitude of endogenous crystals, the range of implant materials and material combinations, and the variability in the formation process of different particles explain the high morphological particle heterogeneity which complicates the diagnostic identification of diagnostic particles.

STUDY DESIGN AND METHODS

A simple histopathological particle algorithm has been designed which allows methodological particle identification based on (1) conventional transmitted light microscopy with a guide to particle size, shape and color, (2) optical polarization criteria and (3) enzyme histochemical properties (oil red staining and Prussian blue reaction). These methods, the importance for particle identification and the differential diagnostics from non-prosthetic materials are summarized in the so-called histopathological particle algorithm.

RESULTS

A total of 35 cases of synovitis and SLIM were analyzed and validated according to these criteria. Based on these criteria and a dichotomous differentiation the complete spectrum of particles in the SLIM and synovia can be defined histopathologically.

CONCLUSION

For histopathological diagnosis a particle score for synovitis and SLIM is recommended to evaluate (1) the predominant type of prothetic wear debris with differentiation between microparticles, and macroparticles, (2) the presence of non-prosthesis material particles and (3) the quantification of particle-association necrosis and lymphocytosis. An open, continuously updated web-based particle algorithm would be helpful to address the issue of particle heterogeneity and include all new particle materials generated in a rapidly changing field.