CSF1 expression in xanthogranulomatous epithelial tumor/keratin-positive giant cell-rich tumor

"Xanthogranulomatous epithelial tumor" (XGET) and "keratin-positive giant cell-rich soft tissue tumor" (KPGCT), two recently described mesenchymal neoplasms, likely represent different aspects of a single entity. Both tumors are composed of only a small minority of tumor cells surrounded by large numbers of non-neoplastic inflammatory cells and histiocytes, suggesting production of a paracrine factor with resulting "landscape effect," as seen in tenosynovial giant cell tumor. Recent evidence suggests that the paracrine factor in XGET/KPGCT may be CSF1, as in tenosynovial giant cell tumor. We hypothesized that CSF1 is overexpressed in XGET/KPGCT. To test our hypothesis, we performed quantitative real time PCR (qPCR) for CSF1 expression and CSF1 RNAscope chromogenic in situ hybridization (CISH) on 6 cases of XGET/KPGCT. All cases were positive with CSF1 CISH and showed increased expression of CSF1 by qPCR. Our findings provide additional evidence that the CSF1/CSF1R pathway is involved in the pathogenesis of XGET/KPGCT. These findings suggest a possible role for CSF1R inhibition in the treatment of unresectable or metastatic XGET/KPGCT.

Bone SPECT/CT in Advanced Diffuse Tenosynovial Giant Cell Tumor of the Wrist

ABSTRACT

Tenosynovial giant cell tumor, previously known as pigmented villonodular synovitis, is a benign low-grade fibrohistiocytic proliferation with hemosiderin deposits in synovial joints. Mostly affecting the knee, it can also manifest in other synovial joints, infrequently also in the wrist. Tenosynovial giant cell tumor typically causes intense radionuclide uptake in all phases in planar bone scintigraphy, making a differentiation from other bone tumors or osteomyelitis difficult, especially in cases associated with extensive bone destruction. We present a case of an unusually advanced and extended tenosynovial giant cell tumor of the wrist in bone scintigraphy, SPECT/CT, radiograph, and MRI.

Identification of potential diagnostic biomarkers for tenosynovial giant cell tumour by integrating microarray and single-cell RNA sequencing data

PURPOSE

Tenosynovial giant cell tumour (TGCT) is a benign hyperplastic and inflammatory disease of the joint synovium or tendon sheaths, which may be misdiagnosed due to its atypical symptoms and imaging features. We aimed to identify biomarkers with high sensitivity and specificity to aid in diagnosing TGCT.

METHODS

Two scRNA-seq datasets (GSE210750 and GSE152805) and two microarray datasets (GSE3698 and GSE175626) were downloaded from the Gene Expression Omnibus (GEO) database. By integrating the scRNA-seq datasets, we discovered that the osteoclasts are abundant in TGCT in contrast to the control. The single-sample gene set enrichment analysis (ssGSEA) further validated this discovery. Differentially expressed genes (DEGs) of the GSE3698 dataset were screened and the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs were conducted. Osteoclast-specific up-regulated genes (OCSURGs) were identified by intersecting the osteoclast marker genes in the scRNA-seq and the up-regulated DEGs in the microarray and by the least absolute shrinkage and selection operator (LASSO) regression algorithm. The expression levels of OCSURGs were validated by an external dataset GSE175626. Then, single gene GSEA, protein-protein interaction (PPI) network, and gene-drug network of OCSURGs were performed.

RESULT

22 seurat clusters were acquired and annotated into 10 cell types based on the scRNA-seq data. TGCT had a larger population of osteoclasts compared to the control. A total of 159 osteoclast marker genes and 104 DEGs (including 61 up-regulated genes and 43 down-regulated genes) were screened from the scRNA-seq analysis and the microarray analysis. Three OCSURGs (MMP9, SPP1, and TYROBP) were finally identified. The AUC of the ROC curve in the training and testing datasets suggested a favourable diagnostic capability. The PPI network results illustrated the protein-protein interaction of each OCSURG. Drugs that potentially target the OCSURGs were predicted by the DGIdb database.

CONCLUSION

MMP9, SPP1, and TYROBP were identified as osteoclast-specific up-regulated genes of the tenosynovial giant cell tumour via bioinformatic analysis, which had a reasonable diagnostic efficiency and served as potential drug targets.

Double Trigger Wrist Caused by 2 Flexor Tendon Sheath Giant Cell Tumors

ABSTRACT

Trigger finger is a relatively common condition affecting the smooth gliding of tendons in the hand. When this entity affects the gliding motion of the wrist, it is termed as trigger wrist. In this article, we report the extremely rare case of a double trigger wrist caused by 2 tendon sheath tumors resulting in 2 trigger points in the motion of the wrist and carpal tunnel syndrome. The patient was managed with surgical excision of the tumors and release of the flexor retinaculum with resolution of symptoms.

Pexidartinib Provides Modest Pain Relief in Patients With Tenosynovial Giant Cell Tumor: Results From ENLIVEN

BACKGROUND

The double-blind, randomized, placebo-controlled phase 3 study of orally administered PLX3397 in patients with pigmented villonodular synovitis or giant cell tumor of the tendon sheath (ENLIVEN) showed that pexidartinib provides a robust objective tumor response in adults with tenosynovial giant cell tumors (TGCT) not amenable to improvement with surgery. Based on these results, in 2019, pexidartinib received accelerated approval in the United States in this population as a breakthrough therapy under an orphan drug designation. However, the ability of pexidartinib to relieve pain in ENLIVEN was not fully detailed, and the relationship between pain relief and objective tumor response was not described.

QUESTIONS/PURPOSES

(1) What level of pain relief was achieved by pexidartinib treatment in ENLIVEN? (2) How was pain relief related to objective tumor responses? (3) How durable was pain relief?

METHODS

The current study included planned primary and exploratory assessments of patient-assessed worst pain at the site of the tumor in the ENLIVEN trial. ENLIVEN was a phase 3 randomized, placebo-controlled clinical trial in which adults with TGCT not amenable to improvement with surgery received pexidartinib or placebo for 24 weeks, after which eligible patients could receive open-label pexidartinib. Of 174 patients assessed for eligibility, 121 were randomized (50% [60] to placebo, 50% [61] to pexidartinib), and 120 were given either placebo or pexidartinib (59 received placebo and 61 received pexidartinib) and were included in an intent-to-treat analysis. Fifty-nine percent (71 of 120) of the overall treated population was female, and 88% (106 of 120) were White. Mean age was 45 ± 13 years. Tumors were mostly in the lower extremities (92% [110 of 120]), most commonly in the knee (61% [73 of 120]) and ankle (18% [21 of 120]). As a secondary outcome, patients scored worst pain at the site of the tumor in the past 24 hours on an 11-point numeric rating scale (NRS). The primary definition of a pain response was a decrease of at least 30% in the weekly mean worst-pain NRS score and increase of less than 30% in narcotic analgesic use between baseline and week 25. Planned exploratory assessments of pain included the frequency of a pain response using alternative thresholds, including a decrease in worst-pain NRS score of 50% or more and a decrease of at least 2 points (minimum clinically important difference [MCID]), the magnitude of pain reduction between baseline and week 25, correlation between worst-pain NRS score and tumor shrinkage by RECIST 1.1 criteria, and the durability of the pain response during the open-label extension. Pain responses during the randomized portion of the trial were compared according to intention-to-treat analysis, with a one-sided threshold of p < 0.025 to reduce the risk of false-positive results. Pain assessment was complete for 59% (35 of 59) of patients in the placebo group and 54% (33 of 61) of patients in the pexidartinib group. Demographic and disease characteristics did not differ between the two treatment groups.

RESULTS

A difference in the primary assessment of a pain response was not detected between pexidartinib and placebo (response percentage 31% [19 of 61] [95% CI 21% to 44%] versus 15% [9 of 59] [95% CI 8% to 27%]; one-sided p = 0.03). In the exploratory analyses, pexidartinib provided a modest improvement in pain (response percentage 26% [16 of 61] [95% CI 17% to 38%] versus 10% [6 of 59] [95% CI 5% to 20%]; one-sided p = 0.02 using the 50% threshold and 31% [19 of 61] [95% CI 21% to 44%] versus 14% [8 of 59] [95% CI 7% to 25%]; one-sided p = 0.02 using the MCID threshold). The least-squares mean change in the weekly mean worst-pain NRS score between baseline and week 25 was larger in patients treated with pexidartinib than placebo (-2.5 [95% CI -3.0 to -1.9] versus -0.3 [95% CI -0.9 to 0.3]; p < 0.001), although the mean difference between the two groups (-2.2 [95% CI -3.0 to -1.4]) was just over the MCID. Improvement in the weekly mean worst-pain NRS score correlated with the reduction in tumor size (r = 0.44; p < 0.001) and tumor volume score (r = 0.61; p < 0.001). For patients in the open-label extension, the change in the worst-pain NRS score from baseline was similar to the change at the end of the randomized portion and just above the MCID (mean -2.7 ± 2.2 after 25 weeks and -3.3 ± 1.7 after 50 weeks of receiving pexidartinib).

CONCLUSION

Based on the current study, a modest reduction in pain, just larger than the MCID, may be an added benefit of pexidartinib in these patients, although the findings are insufficient to justify the routine use of pexidartinib for pain relief.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Tenosynovial giant cell tumor

Tenosynovial Giant Cell Tumor (TGCT) is a group of typically benign lesions arising from the synovium of joints, bursae and tendon sheaths. Depending on their growth pattern and clinical course, they are divided into localized and diffuse types. It is predominantly caused by a mutation in the stromal cells of the synovial membrane leading to overexpression of the colony stimulating factor 1 that recruits CSF1R-expressing cells of the mononuclear phagocyte lineage into the tumor mass. The lesions contain mainly histiocyte-like and synovial cells accompanied by varying numbers of multinucleated giant cells, mononuclear cells, foam cells, inflammatory cells and hemosiderin deposits. The gold standard for detect- ing and monitoring the disease is MRI, where the characteristic hemosiderin accumulation can be best appreciated, but it is a histological examination that is most conclusive. The main treatment is surgical resection of all pathological tissue, but radio- and chemotherapy are also viable options for certain groups of patients.

Pexidartinib Long-Term Hepatic Safety Profile in Patients with Tenosynovial Giant Cell Tumors

Background

Pexidartinib is approved in the U.S. for tenosynovial giant cell tumors (TGCTs). Herein, we assessed the hepatic safety profile of pexidartinib across patients with TGCTs receiving pexidartinib.

Materials, and Methods

Hepatic adverse reactions (ARs) were assessed by type and magnitude of liver test abnormalities, classified as (a) isolated aminotransferase elevations (alanine [ALT] or aspartate [AST], without significant alkaline phosphatase [ALP] or bilirubin elevations), or (b) mixed or cholestatic hepatotoxicity (increase in ALP with or without ALT/AST and bilirubin elevations, based on adjudication). Median follow‐up from initial pexidartinib treatment was 39 months (range, 32–82) in 140 patients with TGCTs across clinical studies NCT01004861, NCT02371369, NCT02734433, and NCT03291288.

Results

In total, 95% of patients with TGCTs (133/140) treated with pexidartinib (median duration of exposure, 19 months [range, 1–76]), experienced a hepatic AR. A total of 128 patients (91%) had reversible, low‐grade dose‐dependent isolated AST/ALT elevations without significant ALP elevations. Five patients (4%) experienced serious mixed or cholestatic injury. No case met Hy's law criteria. Onset of hepatic ARs was predominantly in the first 2 months. All five serious hepatic AR cases recovered 1–7 months following pexidartinib discontinuation. Five patients from the non‐TGCT population (N = 658) experienced serious hepatic ARs, two irreversible cases.

Conclusion

This pooled analysis provides information to help form the basis for the treating physician's risk assessment for patients with TCGTs, a locally aggressive but typically nonmetastatic tumor. In particular, long‐term treatment with pexidartinib has a predictable effect on hepatic aminotransferases and unpredictable risk of serious cholestatic or mixed liver injury.

Implications for Practice

This is the first long‐term pooled analysis to report on the long‐term hepatic safety of pexidartinib in patients with tenosynovial giant cell tumors associated with severe morbidity or functional limitations and not amenable to improvement with surgery. These findings extend beyond what has been previously published, describing the observed instances of hepatic toxicity following pexidartinib treatment across the clinical development program. This information is highly relevant for medical oncologists and orthopedic oncologists and provides guidance for its proper use for appropriate patients within the Pexidartinib Risk Evaluation and Mitigation Safety program.

Pexidartinib is approved in the U.S. for treatment of tenosynovial giant cell tumors (TGCT). This article assesses the hepatic safety profile of pexidartinib in TGCT cases and describes risk mitigation procedures designed to identify any instances of serious liver injury as early as possible to better inform prescribers and patients about this drug.

Clinical and morphological correlations and histopathology of joint damage in patients with diffuse-type tenosynovial giant cell tumor

OBJECTIVE

Introduction: Tenosynovial giant cell tumor (TSGCT) (synonym - pigmented villonodular synovitis) - is a rare benign proliferative lesion of the synovial sheath, localized in the joint capsule, bursa or tendon sheath and characterized by locally destructive growth. Depending on the prevalence within the joint elements, the presence of a capsule around the tumor, histophotographic features of cell structure and clinical behavior TSGCT can be divided to localized or diffuse type. The aim of the study was researching of histopathological properties of diffuse-type TSGCT, determine the parameters its morphological indicators and to find out the correlation between these morphological and clinical parameters.

PATIENTS AND METHODS

Materials and methods: The research material was used biopsy (resect) of pathological lesions from 50 patients who were diagnosed and histologically verified diffuse-type TSGCT. Microscopic examinations of the stained sections and their photo archiving were carried out with use of a Olympus-CX 41 light optical microscope. Group measurable parameters (mean values and Pearson tetrachoric index (association coefficient) were calculated in groups of comparison for morphological and clinical indices of TSGCT. The mean values were compared by Student's test, P value of ≤0.1 was considered statistically significant.

RESULTS

Results: Correlation analysis of indicators that accounted for the pairs of cases «clinic - morphology» revealed the relationships, that had the highest parameters of the association coefficient between such indicators: «presence of villous growths» - «severity of hemosiderosis» (if hypertrophied synovial villi available, with vascular injection and pronounced proliferation of synovial cells, there is also a significant accumulation of hemosiderin pigment); «presence of villous growths» - «type of predominant cellular proliferates» (if cells of TSGCT diffuse type consists of monotonous sheets of stromal cells, with uniform, oval to reniform nuclei, the proliferation of villi in synovial layer is non-distinctive); «presence of nodes» - «kind of stroma» (if nodes predominate, their histological structure is mainly represented by polymorphic clusters of synovitis cells in the form of cells, strands, chains, solid formations, among immature connective tissue with low hyalinosis); «cell size (area, cm²)» - «severity of haemosiderosis» and «cell size (area, cm²)» - «the number of multinucleated giant cells» (there is a pronounced deposition of pigment and accumulation of osteoclast-like multinucleated giant cells type, although usually their number is relatively small compared to the localized type of TSGCT).

CONCLUSION

Conclusions: Morphological parameters, that we have identified, characterize pathological changes in the tissues of TSGCT; careful analysis of the frequency of their occurrence in the different comparison groups made it possible to establish intergroup differences and correlations between individual indicators, which were previously unknown or not obvious. Our study was determine to analyze of incidence rates and correlation relationships, revealed some previously unknown differences and dependencies that are important for understanding the pathogenesis, improvement of diagnosis and prognosis of diffuse-type TSGCT.