Challenges of denosumab in giant cell tumor of bone, and other giant cell-rich tumors of bone

Giant Cell Tumor of Soft Tissue: An Updated Review

Giant cell tumor of soft tissue (GCTST) is a locally aggressive mesenchymal neoplasm of intermediate malignancy that predominantly occurs in the superficial soft tissue of the extremities. It is histologically similar to a giant cell tumor of bone (GCTB) and shows a mixture of round to oval mononuclear cells and osteoclast-like multinucleated giant cells. Currently, immunohistochemistry plays a very limited role in the diagnosis of GCTST. Primary or secondary malignant GCTST has recently been described and tumors exhibiting high-grade histological features demonstrate higher rates of distant metastasis. GCTST lacks the H3-3A gene mutations that are identified in the vast majority of GCTBs, suggesting a different pathogenesis. Surgery is the standard treatment for localized GCTST. Incomplete surgical resection is usually followed by local recurrence. Radiation therapy may be considered when the close proximity of critical structures prevents microscopically negative surgical margins. The systemic treatment options for advanced or metastatic disease are very limited. This review provides an updated overview of the clinicoradiological features, pathogenesis, histopathology, and treatment for GCTST. In addition, we will discuss the differential diagnosis of this peculiar neoplasm.

Management of RANKL-mediated Disorders With Denosumab in Children and Adolescents: A Global Expert Guidance Document

CONTEXT

Denosumab is an effective treatment for many receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated disorders but there are potential safety considerations and limited data to guide its use in children and adolescents.

OBJECTIVE

This document seeks to summarize the evidence and provide expert opinion on safe and appropriate use of denosumab in pediatric RANKL-mediated disorders.

PARTICIPANTS

Ten experts in pediatric bone and mineral medicine from 6 countries with experience in the use of denosumab participated in the creation of this document.

EVIDENCE

Data were sourced from the published literature, primarily consisting of case reports/series and review articles because of the lack of higher level evidence. Expert opinion of the authors was used substantially when no published data were available.

CONCLUSION

Denosumab is an effective treatment for RANKL-mediated disorders in children and adolescents but is often not curative and, in some cases, is best used in conjunction with surgical or other medical treatments. Careful multidisciplinary planning is required to define the goals of treatment and expert oversight needed to manage the risk of mineral abnormalities. Substantive, collaborative research efforts are needed to determine optimal treatment regimens and minimize risks.

Unusual Presentation of a Giant Cell Tumor of the Bone: A Case Report

Bone giant cell tumors (GCTs) are rare, non-cancerous tumors that mostly affect the meta-epiphyseal region of long bones in the legs and arms. We are reporting a case of GCT of bone of a 14-year-old male; it usually occurs in the age group of 20-40 years. The presence of multinucleated giant cells and stromal cells in the proximal diaphysis of the left tibia serves as a distinguishing characteristic. The majority of GCTs are benign; they have the potential to induce bone loss and can be locally aggressive. Treatment options often include surgery, and in some cases, medications like denosumab may be used to help shrink the tumor or manage recurrent cases.

Diagnosis and monitoring denosumab therapy of giant cell tumors of bone: radiologic-pathologic correlation

OBJECTIVE

To determine the value of CT and dynamic contrast-enhanced (DCE-)MRI for monitoring denosumab therapy of giant cell tumors of bone (GCTB) by correlating it to histopathology.

MATERIALS AND METHODS

Patients with GCTB under denosumab treatment and monitored with CT and (DCE-)MRI (2012-2021) were retrospectively included. Imaging and (semi-)quantitative measurements were used to assess response/relapse. Tissue samples were analyzed using computerized segmentation for vascularization and number of neoplastic and giant cells. Pearson's correlation/Spearman's rank coefficient and Kruskal-Wallis tests were used to assess correlations between histopathology and radiology.

RESULTS

Six patients (28 ± 8years; five men) were evaluated. On CT, good responders showed progressive re-ossification (+7.8HU/month) and cortical remodeling (woven bone). MRI showed an SI decrease relative to muscle on T1-weighted (-0.01 A.U./month) and on fat-saturated T2-weighted sequences (-0.03 A.U./month). Time-intensity-curves evolved from a type IV with high first pass, high amplitude, and steep wash-out to a slow type II. An increase in time-to-peak (+100%) and a decrease in Ktrans (-71%) were observed. This is consistent with microscopic examination, showing a decrease of giant cells (-76%), neoplastic cells (-63%), and blood vessels (-28%). There was a strong statistical significant inverse correlation between time-to-peak and microvessel density (ρ = -0.9, p = 0.01). Significantly less neoplastic (p = 0.03) and giant cells (p = 0.04) were found with a time-intensity curve type II, compared to a type IV. Two patients showed relapse after initial good response when stopping denosumab. Inverse imaging and pathological findings were observed.

CONCLUSION

CT and (DCE-)MRI show a good correlation with pathology and allow adequate evaluation of response to denosumab and detection of therapy failure.

Denosumab in Giant Cell Rich Tumors of Bone: An Open-Label Multicenter Phase II Study

BACKGROUND

Since giant cell tumors of bone (GCTB) and other giant cell rich tumors of bone (GCRTB) share the histological presence of osteoclastic giant cells and expression of RANK/RANKL, we hypothesized that GCRTB will respond similarly to denosumab as GCTB. The primary objective of this study was to determine the efficacy of denosumab in patients with GCRTB that have recurred or require morbid surgery.

METHODS

In this open-label, multicenter, phase II trial, patients with GCRTB were included (June 2018-March 2020). Recruitment was stopped because of low accrual. Patients received denosumab (120 mg) subcutaneously (SC) on day 1 of every 4-week cycle with a loading dose of 120 mg SC on days 8 and 15.

RESULTS

Three patients were enrolled. One withdrew consent before start of study. The remaining patients had central giant cell granuloma of the jawbone (CGCG). Median treatment duration was 15 cycles (range 12-18). In both subjects, improvement in ossification of lesions was seen. Median follow-up was 28.5 months (range 20-37). One patient developed a recurrence for which surgery was performed.

CONCLUSION

Due to critical emerging real-world data of denosumab in GCRTBs, the study was prematurely stopped and not supportive of use of denosumab for this indication. (ClinicalTrials.gov Identifier: NCT03605199).

Denosumab for giant cell tumors of bone from 2010 to 2022: a bibliometric analysis

Giant cell tumors of the bone (GCTB) are considered moderately malignant bone tumors. Denosumab, as a neoadjuvant therapy, provides new possibilities for treating GCTB. However, even after multiple studies and long-term clinical trials, there are limitations in the treatment process. Research data and Medical Subject Headings terms related to denosumab and GCTB were collected from January 2010 to October 2022 using the Web of Science and MeSH ( https://meshb.nlm.nih.gov ) browsers. These data were imported into CiteSpace and VOSviewer softwares for bibliometric analysis. Overall, 445 publications on denosumab and GCTB were identified. Over the last 12 years, the growth rate of the total number of publications has remained relatively stable. The USA published the highest number of articles (83) and had the highest centrality (0.42). Amgen Inc. and Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) First Ortoped Rizzoli were identified as the most influential institutions. Many authors have made outstanding contributions to this field. Lancet Oncology had the highest journal impact factor (54.433). Local recurrence and drug dosage are current research hotspots, and future development trends will mainly focus on prognostic markers of GCTB and the development of new therapies. Further research is required to analyze denosumab's safety and efficacy and understand its local recurrence of GCTB, to identify the optimal dose. Future progress in this field will likely focus on exploring new diagnostic and recurrence markers to monitor disease progression and examine new therapeutic targets and treatment strategies.

Giant Cell Tumour of Bone: A Comprehensive Review of Pathogenesis, Diagnosis, and Treatment

The benign aggressive tumour known as a giant cell tumour of bone (GCTB) frequently affects the knee bones. Patients suffering from GCTB present with pain, swelling, joint effusion, loss of ability to bear weight on the involved extremity and a restriction in the range of motion of the afflicted joint may also exist, depending on the tumour's size. GCTB makes up 20% of benign skeletal tumours and 5% of all primary bone tumours. Although it has an equal distribution of the sexes, the majority reveal a higher frequency among women. Eighty per cent of GCTB instances were recorded in patients between the ages of 20 and 50 during the third decade. The femur, tibia and radius are where GCTB is most frequently discovered. Lesions can be rated using the Campanacci grading method based on the plain radiograph's results. Plain radiography, CT and MRI are used to diagnose the tumour. Surgery is the only curative treatment which is determined by the Campanacci grade and the tumour's location. Recurrence of GCTB is observed in about 25% of patients, with curettage being associated with rates as high as 50%. We evaluated the GCTB-related articles and summarised the developments in diagnosis, treatment and reducing risk of recurrence.

Genetic characterization of a novel organoid from human malignant giant-cell tumor

Malignant giant-cell tumors are extremely rare bone sarcomas that transform from conventional giant-cell tumors during long periods of treatment. Owing to their rarity, no further analysis of their molecular pathogenesis exists, and thus, no standard treatment has been established. Recently, organoid culture methods have been highlighted for recapturing the tumor microenvironment, and we have applied the culture methods and succeeded in establishing patient-derived organoids (PDO) of rare sarcomas. This study aimed to investigate the genomic characteristics of our established novel organoids from human malignant giant-cell tumors. At our institute, we treated a patient with malignant giant-cell tumor. The remaining sarcoma specimens after surgical resection were cultured according to the air-liquid interface organoid-culture method. Organoids were xenografted into NOD-scid IL2Rgnull mice. The developed tumors were histologically and genomically analyzed to compare their characteristics with those of the original tumors. Genetic changes over time throughout treatment were analyzed, and the genomic status of the established organoid was confirmed. Organoids from malignant giant-cell tumors could be serially maintained using air-liquid interface organoid-culture methods. The tumors developed in xenografted NOD-scid IL2Rgnull mice. After several repetitions of the process, a patient-derived organoid line from the malignant giant-cell tumor was established. Immunohistochemical analyses and next-generation sequencing revealed that the established organoids lacked the H3-3A G34W mutation. The xenografted organoids of the malignant giant-cell tumor had phenotypes histologically and genetically similar to those of the original tumor. The established organoids were confirmed to be derived from human malignant giant-cell tumors. In summary, the present study demonstrated a novel organoid model of a malignant giant-cell tumor that was genetically confirmed to be a malignant transformed tumor. Our organoid model could be used to elucidate the molecular pathogenesis of a malignant giant-cell tumor and develop novel treatment modalities.

Central Giant Cell Reparative Granuloma (CGCRG) of the Jaw in Children Treated with Neoadjuvant Bisposphonates: Review and a Case Report

Central giant cell reparative granuloma (CGCRG) of the jaw is a neoformation localized in the mandible or in the maxillary bone and characterized by fibrous tissue, osteoclast-like giant cells and reactive bone formation. The CGCRG is a less frequent benign tumor but sometimes it is characterized by an aggressive behavior with a very rapid growth. It affects the young adults mainly and the children occasionally. Nowadays no medication therapy is approved for CGCRG in pediatric cases. We present a case of an aggressive form of a mandibular CGCRG in a 5-year child with Arnold-Chiari syndrome. This case is unique for the use of bisphosphonates (BPs) as neoadjuvant therapy in pediatrics. The therapy were administrated with the purpose of arresting the rapid growth of the tumor in order to avoid a demolitive surgery to the young patient. The child was without symptoms and presented an unusual swelling in the left mandible developed in a few weeks. The lesion was diagnosed by a CT scan and it was confirmed by a biopsy performed for histopathological assessment a few days later. The drug therapy consisted of seven cycles iv of Zoledronate associated to Calcium Gluconate. The child was closely observed through clinical and serological evaluations during the following months. About five months after the last cycle of BPs the child underwent CT scan and a conservative surgical treatment, consisted in a deep curettage, was programmed. Seven months after surgery the aesthetic profile of the patient improved and CT scan reported a significant calcic neoapposition in the area of the previous bone lesion. After more than one year from surgery, no relapse was observed. This case report demonstrates that BPs can be used safely in pediatric patients with CGCRG. Especially BPs could have a role as neoadjuvant therapy: If administrated before surgical treatment BPs avoid the necessity of resective surgery and reduce the risk of recurrence in pediatric CGCRG after conservative curettage.

Oral giant cell tumor or giant cell granuloma: How to know?

Introduction

The distinction between giant cell tumors and giant cell granulomas is challenging, as both entities have overlapping diagnostic criteria, especially in oral locations. The two entities have similar clinical and radiological presentations, but they differ in their prognoses.

Objective

The main objective of this study was to list the clinical, radiological, histological, and prognostic features of maxillomandibular giant cell tumors and giant cell granulomas cases n order to assess their value as a diagnostic referral factor that may allow the distinction between maxillo-mandibular giant cell granuloma and giant cell tumor.

Study design

Data of maxillomandibular giant cell granulomas and giant cell tumors were assessed through a scoping review and a pre-existing systematic review of literature. We have also realized a bicentric retrospective study.

Results

Various criteria facilitate the differential diagnosis like age, size, locularity and presence of necrosis zone but not the gender. The most discriminating factors was symptomatology (reported in 72% of GCTs while only 15% of GCGs) and the distribution pattern of giant cells in the stroma (homogeneously dispersed in 80% of GCTs versus grouped in clusters in 86.7% of GCGs). Recurrences were most described for giant cell tumors than giant cell granulomas. Malignant transformation and pulmonary metastasis were exclusively reported for giant cell tumors.

Conclusion

As clinical and radiological elements are not sufficient to distinguish between these two entities, immunohistochemistry and molecular genetics can be represent diagnostic biomarkers to distinguish giant cell granulomas and giant cell tumors in oral cavity. We have attempted to define the main criteria for the differentiation of giant cell tumor and giant cell granuloma and propose a decision tree for the management of single maxillomandibular giant cell lesions.

Resection and reconstruction with and without neoadjuvant denosumab in campanacci grade III giant cell tumors of proximal humerus: a retrospective comparative study

BACKGROUND

Giant cell tumors (GCT) of the proximal humerus are rarely reported case that requires complex surgeries due to involvement of the shoulder joint. Therefore, we report the first retrospective comparative study where the postoperative functional outcomes, recurrence rate and complications in patients who underwent arthrodesis of shoulder after resection of grade III GCT with and without neoadjuvant denosumab are compared.

METHODS

A retrospective review of eight cases of grade III GCT of proximal humerus receiving resection and fibular strut graft and arthrodesis between January 2014 and December 2019 is performed. They were stratified into two groups: one group of four patients received once-weekly denosumab 120 mg for 4-weeks before resection and reconstruction, while the other group of four patients did not receive denosumab before surgery. Primary outcomes included the functional outcomes assessed by revised Musculoskeletal tumor society (MSTS) score and shoulder pain and disability index (SPDI) at 6-weeks and 12-months postoperatively while secondary outcomes included complications and recurrences.

RESULTS

There was no significant difference in terms of SPDI at 6 weeks and 12 months, MSTS at 12 months, complications, recurrence among denosumab and non-denosumab groups. At 6-weeks follow-up, a significantly better pain score in SPDI and MSTS was acquired in the denosumab group.

CONCLUSIONS

Resection and reconstruction with or without neoadjuvant denosumab for Grade III GCT of proximal humerus had similar functional outcomes and with no major differences in recurrence and complications. Hence, postoperative pain relief while long-term benefits were not discovered with the use of neoadjuvant denosumab.

Fifty years of bone tumors

There have been enormous advances in the treatment of bone tumors over the past half-century. The most notable of these has been the transition from amputation as the standard of care to limb salvage surgery. This transition is the result of advances in imaging techniques, accurate diagnosis, systemic therapies (including chemotherapy), and prosthetic design for the reconstruction of musculoskeletal defects. Advances have also been made in the management of benign and metastatic bone tumors.

RANKL inhibition for giant cell lesions of the jaw: A retrospective cohort analysis

BACKGROUND

In all giant-cell-rich lesions (GCRL) occurring in bone, a common underlying excessive RANKL expression is held responsible for the osteolytic activity. Apart from giant cell tumour of bone (GCTB), systematic outcome analysis of RANKL inhibition in other GCRL is unavailable. The aim of this study is to assess the efficacy and safety of a 1-year denosumab protocol in giant cell lesions of the jaw (GCLJ).

METHODS

A retrospective cohort study was conducted compromising patients treated with a 1-year protocol of monthly subcutaneously administered 120 mg denosumab. Objective tumour response based on histology and imaging was used to calculate objective tumour response rate, progression-free survival (PFS) and time to progression. Type, severity and frequency of adverse events were recorded in a standardised way to assess safety.

RESULTS

Twenty patients, predominantly female (90%), were included. Fifty-five per cent of lesions were located in the mandible; most classified as aggressive lesions (90%). Thirty-five per cent (7/20) of cases were either recurrent after prior treatment or progressive, while on other drug treatment. Objective tumour response rate was 100% after 12 months of treatment. Median PFS was 50.4 months (95% CI 38.0-62.8) with a cumulative PFS rate of 22.6% (95% CI 1.8-43.4) at 5 years follow-up. Median time to progression was 38.4 months (95% CI 26.0-50.8). Treatment was well tolerated, and none of the patients had to interrupt therapy for toxicity.

CONCLUSION

High-dose denosumab is effective and safe in achieving a complete response in GCLJ within 12 months. The high long-term relapse rate after treatment cessation is the main obstacle for denosumab to become standard treatment for GCLJ.

The Activation of PDGFRβ on Mononuclear Stromal/Tumor Cells in Giant Cell Tumor of Bone After Denosumab Treatment. An Immunohistochemical Study of Five Cases

Due to the relatively high recurrence rate and the destructive nature of the tumor, the treatment of giant cell tumor is still a challenge. Denosumab appeared to be a promising candidate as a therapeutic drug. However, several studies have reported that tumors can recur during/after treatment with denosumab. Based on activated receptor tyrosine kinase signaling pattern of the stromal/tumor cells, a combination treatment with denosumab and sunitinib has recently been proposed to inhibit recurrences. This prompted us to investigate the PDGFRβ expression of five denosumab treated cases using both primary and recurrent tumors during and after denosumab treatment. In addition, to recognise morphological changes, immunohistochemical analysis of H3F3A and PDGFRβ was also performed. As an effect of denosumab treatment, the permanent absence of giant cells associated with severe to mild fibrosis was the most consistent morphological change, but H3F3A positive stromal/tumor cells were observed in all cases. Furthermore, an increased immunopositivity of PDGFRβ in stromal/tumor cells was evident in all recurrent cases during denosumab treatment. Upon tumor recurrence (after the discontinuation of denosumab treatment) the intensity of PDGFRβ immunostaining in stromal/tumor cells was restored/decreased. Our results confirm (for the first time) the activation of PDGFRβ on mononuclear stromal/tumor cells at protein level as an effect of denosumab treatment, which has so far only been demonstrated by phosphoprotein array analysis (protein lysates). The decreased PDGFRβ activity after the discontinuation of denosumab treatmeant and the increased PDGFRβ activity during denosumab treatment underlines the need for denosumab and sunitinib combination therapy.

Comprehensive treatment outcomes of giant cell tumor of the spine: A retrospective study

There is no consensus on a treatment strategy for spinal giant cell tumor of bone (GCTB) because of the difficulty in their treatment. Treatment options often include the use of the controversial denosumab, an antibody therapy aimed at tumor shrinkage, different curettage techniques, resection, or a combination of these therapies. The current study aimed to identify treatment methods associated with favorable outcomes in patients with spinal GCTB. We retrospectively reviewed 5 patients with spinal GCTB, including patients with tumors of the sacrum, treated at our hospital between September 2011 and November 2020. Two men and 3 women were included in the study. The median follow-up period was 74 months (range: 14-108 months). We surveyed the tumor site, treatment method, denosumab use, and outcomes. The median age was 17 years (range: 17-42 years). There were 2 cases of sacral GCTB and 1 case each of lumbar, cervical, and thoracic vertebral GCTB. The comorbidities observed included hepatitis, malignant lymphoma, atopic dermatitis, and asthma. The treatment method included zoledronic acid after embolization and denosumab, denosumab only, curettage and posterior fusion, and curettage resection after embolization and anterior and posterior fusion. Denosumab was used in all cases. Three patients were continuously disease-free, 1 patient with no evidence of disease, and 1 patient alive with disease. Aggressive treatment, especially surgical treatment, may lead to good results in spinal GCTB.

The effective distance and cooling rate of liquid nitrogen-based adjunctive cryotherapy for bone tumors ex vivo

BACKGROUND

Liquid nitrogen (LN) has been used as an adjuvant cryotherapy for bone tumors including giant-cell tumor of the bone (GCTB) to remove residual tumor cells after curettage. This study evaluated variables related to the efficacy of LN-based cryoablation in the context of adjuvant treatment of GCTB using porcine femur bone model.

METHODS

A porcine femur bone model was adopted to simulate intralesional cryotherapy. A LN-holding cavity (point 1, nadir) in the medial epicondyle, 4 holes (points 2-5) in the shaft situated 5, 10, 15, and 20 mm away from the proximal edge of the cavity, and 2 more holes (points 6 and 7) in the condyle cartilage (10 and 20 mm away from the distal edge of the cavity) were made. The cooling rate was compared between the 5 points. The cellular morphological changes and DNA damage in the GCTB tissue attributable to LN-based cryotherapy were determined by H&E stain and TUNEL assay. Cartilage tissue at points 6 and 7 was examined for the extent of tissue injury after cryotherapy.

RESULTS

The temperature kinetics at points 1, 2 reached the reference target and were found to be significantly better than the reference (both p < 0.05). The target temperature kinetics were not achieved at points 4 and 5, which showed a significantly lower cooling rate than the reference (both p < 0.001) without reaching the -60°C target. Compared with untreated samples, significantly higher proportion of shrunken or apoptotic cells were found at points 1-3; very small proportion were observed at points 4, 5. Significantly increased chondrocyte degeneration was observed at point 6, and was absent at point 7.

CONCLUSION

The cryotherapy effective range was within 5 mm from nadir. Complications were restricted to within this distance. The cooling rate was unchanged after three repeated cycles of cryotherapy.

Central Giant Cell Granuloma in the Mandibular Condyle in a Teenager. A Case Report with Literature Review

Central giant cell granulomas (CGCG) are not common in the mandibular condyle. In teenagers, the problem is more complex because of difficulties in diagnosis and treatment involving the potential growth of the mandibular process and development of the face. In this short communication a case is presented of an eleven-year-old female under diagnosis of central giant cell granuloma affecting the mandibular condyle treated surgically in two steps using a condylectomy and vertical ramus osteotomy at the first time and later orthognathic surgery, showing the clinical evolution after 13 years of follow-up. In addition, we performed a review of the scientific reports related to CGCG in the mandibular condyle to compare this treatment with others, in terms of follow-up and results. We concluded that the CGCG affecting the mandibular head can be properly treated with low condilectomy, vertical mandibular ramus sliding osteotomy, and discopexy.

Outcomes in Bone Giant Cell Tumors Treated With Surgical Resection With and Without Denosumab Injection: A Single-Institution Retrospective Study

Background: Giant cell tumors of the bone (GCTB) are rare, benign, aggressive, recurrent tumors that are most often found at the ends of long bones. They account for 5% of all primary bone tumors and 20% of all benign bone tumors. The clinical features of GCTB include local swelling, pain, and limitations in joint movement. Approximately half of GCTB arise around the knee joint, affecting either the distal femur or proximal tibia. Tissue biopsy reveals an excess of multinucleated giant cells on a stromal cell background, indicating a diagnosis. Intralesional curettage is used to treat GCTB and is associated with minimal disability; however, local recurrence may occur in many patients. Resection and endoprosthetic repair or bone graft reconstruction are often used to treat GCTB near the joint. To our knowledge, there are currently no studies on this topic in the city of Jeddah, where we conducted our study. Our aim was to evaluate the outcome of surgical resection accompanied by denosumab injection compared to that of surgery alone in treating GCTB.

Methods: All cases of GCTB at King Abdulaziz Medical City, Jeddah, between January 2008 and December 2018, that fulfilled the inclusion and exclusion criteria were included. All cases of GCTB in the pre-specified period were classified as surgical resection with denosumab injection or surgical resection alone. The outcomes of the two modalities were compared. Recurrence was investigated in patients belonging to both the groups.

Results: Twenty-six cases that met the inclusion criteria were included in the study and the data were analyzed. The subjects were divided into two groups: denosumab and surgery (n = 7) and surgery alone (n = 19). Patients treated with denosumab and surgery had a higher recurrence rate (57%); however, the difference was not significant (p = 0.407).

Conclusion: Our study showed that when comparing local recurrence after curettage in patients treated with denosumab and patients who did not receive it, preoperative denosumab therapy was associated with an increased incidence of local recurrence. We recommend a systematic review that can include more studies in this field to acquire more definitive results regarding this topic.

Updated concepts in treatment of giant cell tumor of bone

PURPOSE OF REVIEW

Giant cell tumors of bone (GCTB) are intermediate, locally aggressive primary bone tumors. For conventional GCTB, surgery remains treatment of choice. For advanced GCTB, a more important role came into play for systemic therapy including denosumab and bisphosphonates over the last decade.

RECENT FINDINGS

In diagnostics, focus has been on H3F3A (G34) driver mutations present in GCTB. The most frequent mutation (G34W) can be detected using immunohistochemistry and is highly specific in differentiating GCTB from other giant cell containing tumors. PD-L1 expression can be used as biological marker to predict higher recurrence risks in GCTB patients.The use of bisphosphonate-loaded bone cement is under investigation in a randomized controlled trial. A new technique consisting of percutaneous microwave ablation and bisphosphonate-loaded polymethylmethacrylate cementoplasty was proposed for unresectable (pelvic) GCTB.Increased experience with use of denosumab raised concern on elevated recurrence rates. However, conclusions of meta-analyses should be interpreted with risk of indication bias in mind. Several small studies are published with short-course denosumab (varying from 3 to 6 doses). One small trial directly compared denosumab and zoledronic acid, with no statistical differences in radiological and clinical outcome, and nonsignificantly higher recurrence rate after denosumab. As bisphosphonates directly target neoplastic stromal cells in GCTB, larger directly comparative trials are still warranted.

SUMMARY

Neoadjuvant denosumab is highly effective for advanced GCTB, and a short-course is advised to facilitate surgery, whereas increased recurrence rates remain of concern. Randomized controlled trials are conducted on bisphosphonate-loaded bone cement and on optimal dose and duration of neoadjuvant denosumab. PD-L1 could be a potential new therapy target in GCTB.

Clinical and Radiologic Response of Central Giant Cell Granuloma to Denosumab: A 6-Year Prospective Observational Study

Central giant cell granuloma (CGCG) is a rare lesion of the jaw occurring in young adults and adolescents. Surgery, the traditional mainstay of therapy, is associated with significant morbidity. Denosumab, a humanised monoclonal antibody to RANKL, is effective in a related entity, giant cell tumour of bone (GCTB), but experience in the more indolent CGCG is limited. This prospective observational study of all denosumab-treated CGCG at a tertiary referral centre (2015-2021) aimed to evaluate the safety, efficacy and recurrence risk using denosumab in CGCG at lower-frequency dosing than used for GCTB. All received standardised, time-limited courses of denosumab 120 mg with stepwise increase in dosing interval based on response. They were followed for up to 75 months using a radiation-minimising protocol: 3-monthly clinical, biochemical and radiological assessment (orthopantomograms, cone beam CT). Eight patients, median age 20.5 years [IQR 6], received 13 initial doses [IQR 10] of denosumab 120 mg. Radiologic response was seen after 5.5 doses [IQR 4.5]: ossification in all and size reduction in three. Recurrence occurred in four of seven completing therapy, observed 12 months post-cessation [IQR 6.5]. Larger baseline size, aggressive subtype and fewer than 12 initial doses were more common in the recurrence group. There was no osteonecrosis of the jaw. Hypocalcaemia occurred in one receiving modified dosing. This study represents the largest, most diverse cohort of denosumab-treated CGCG with the longest follow-up in literature. It demonstrates the efficacy of lower-frequency, time-restricted course of denosumab but highlights the risk of recurrence. Long-term follow-up is critical.

A Rationale for the Activity of Bone Target Therapy and Tyrosine Kinase Inhibitor Combination in Giant Cell Tumor of Bone and Desmoplastic Fibroma: Translational Evidences

Giant cell tumor of bone (GCTB) and desmoplastic fibroma (DF) are bone sarcomas with intermediate malignant behavior and unpredictable prognosis. These locally aggressive neoplasms exhibit a predilection for the long bone or mandible of young adults, causing a severe bone resorption. In particular, the tumor stromal cells of these lesions are responsible for the recruiting of multinucleated giant cells which ultimately lead to bone disruption. In this regard, the underlying pathological mechanism of osteoclastogenesis processes in GCTB and DF is still poorly understood. Although current therapeutic strategy involves surgery, radiotherapy and chemotherapy, the benefit of the latter is still debated. Thus, in order to shed light on these poorly investigated diseases, we focused on the molecular biology of GCTB and DF. The expression of bone-vicious-cycle- and neoangiogenesis-related genes was investigated. Moreover, combining patient-derived primary cultures with 2D and 3D culture platforms, we investigated the role of denosumab and levantinib in these diseases. The results showed the upregulation of RANK-L, RANK, OPN, CXCR4, RUNX2 and FLT1 and the downregulation of OPG and CXCL12 genes, underlining their involvement and promising role in these neoplasms. Furthermore, in vitro analyses provided evidence for suggesting the combination of denosumab and lenvatinib as a promising therapeutic strategy in GCTB and DF compared to monoregimen chemotherapy. Furthermore, in vivo zebrafish analyses corroborated the obtained data. Finally, the clinical observation of retrospectively enrolled patients confirmed the usefulness of the reported results. In conclusion, here we report for the first time a molecular and pharmacological investigation of GCTB and DF combining the use of translational and clinical data. Taken together, these results represent a starting point for further analyses aimed at improving GCTB and DF management.

Giant Cell Tumor of Bone: A Single Center Study of 115 cases

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Giant cell tumor of bone (GCTB) is a rarely metastasizing, locally aggressive tumor.

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GCTB recurs frequently after intralesional curettage.

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Denosumab is a potential neoadjuvant treatment option for borderline resectable lesions.

Background

Giant cell tumor of bone (GCTB) is a locally aggressive bone tumor that represents about 4–5% of all primary bone tumors. It is characterized by aggressive growth, possible recurrence after surgical treatment and, in rare cases, metastasis. Surgical management is the primary treatment and may include intralesional curettage with adjuvants or, in rare cases, wide resection. In recent years the monoclonal antibody denosumab has been introduced as a potential (neo-)adjuvant systemic treatment option for patients with borderline resectable or unresectable lesions. Currently several studies reported that the use of denosumab prior to curettage possibly increase the risk of local recurrence.

Methods

In this retrospective study we reviewed 115 cases of GCT with a mean follow-up of 65.6 (24–404) months who underwent a surgical treatment with or without preoperative denosumab therapy in our institution. Potential risk factors for LR and complications were analyzed.

Results

The study includes 47 male (40.9%) and 68 female (59.1%) patients with a mean age of 33.9 (10–77) years and a mean follow-up of 65.6 (24–404) months. Denosumab was used in 33 (28.7%) cases, in 14 cases (12.2%) in a neoadjuvant setting and in 17 cases preoperatively before re-curettage (14.8%) after LR. In 105 cases (91.3%) an intralesional curettage was performed. The overall LR rate was 47.8% (55 cases). Patients who underwent intralesional curettage and bone cement augmentation without neoadjuvant denosumab treatment had LR in 42.2% (38/90) of the cases. Patients who underwent neoadjuvant denosumab treatment prior to curettage had LR in 28.6% (4/14). Re-recurrence was frequent in patients with neoadjuvant denosumab treatment who had LR after initial curettage (50%, 8/16). After wide resection and endoprosthetic replacement one case (20%) of local recurrence was detectable (1/5 cases).

Conclusions

GCTB recurs frequently after intralesional curettage and cement augmentation. While denosumab is a potential (neo-)adjuvant treatment option that might be used for lesions that are difficult to resect, surgeons should be aware that LR is still frequent.

Utility of intraoperative magnetic resonance imaging for giant cell tumor of bone after denosumab treatment: a pilot study

BACKGROUND

Giant cell tumor of bone (GCTB) is an intermediate but locally aggressive neoplasm. Current treatment of high-risk GCTB involves administration of denosumab, which inhibits bone destruction and promotes osteosclerosis. However, denosumab monotherapy is not a curative treatment for GCTB and surgical treatment remains required. Denosumab treatment complicates surgery, and the recurrence rate of GCTB is high (20%-30%).

PURPOSE

To examine the utility of intraoperative magnetic resonance imaging (iMRI) for detection and reduction of residual tumor after denosumab treatment and to investigate the utility of iMRI, which is not yet widely used.

MATERIAL AND METHODS

We enrolled five patients who received denosumab for a median period of eight months (range 6-12 months). Surgery was performed when the degree of osteosclerosis around the articular surface was deemed appropriate. We performed iMRI using a modified operation table to identify residual tumor after initial curettage and evaluated the rate of detection of residual tumor by iMRI, intraoperative and postoperative complications, exposure time of iMRI, and operation time.

RESULTS

Suspected residual tumor tissue was identified in all five cases and was confirmed by histopathology after additional curettage. The rate of detection of residual tumor by iMRI was 100%. Residual tumor was located in sites which were difficult to remove due to osteosclerosis. The iMRI was performed safely and without trouble. During the median follow-up period of 10 months (range 6-24 months), no adverse events or recurrences occurred.

CONCLUSION

Intraoperative MRI could contribute to the reduction of residual tumor tissue and it may prevent recurrence of GCTB after denosumab therapy.

Giant Cell Tumor of Bone Versus Tenosynovial Giant Cell Tumor - Similarities and Differences

Giant cell tumor of bone (GCTB) and tenosynovial giant cell tumor (TGCT) share misleadingly similar names, soft texture and brown color macroscopically, osteoclast-like multinucleated giant cells microscopically and localisation in the musculoskeletal system. However, these two tumor types are biologically and clinically two distinct entities with different natural courses of progression and considerably different modes of surgical and medical treatment. In this article, we provide a detailed update on the similarities and the differences between both tumor types.GCTB is a locally aggressive osteolytic bone tumor, commonly seen in patients in their third decade of life. It usually occurs as a solitary lesion in the meta-epiphyseal region of long bones. It can be diagnosed using plain radiographic imaging, CT radiography or MRI to estimate the tumor extent, soft tissue and joint involvement. GCTB is usually treated with intralesional excision by curettage. Systemically, it can be treated with bisphosphonates and denosumab or radiotherapy.TGCT is a rare, slowly progressing tumor of synovial tissue, affecting the joint, tendon sheath or bursa, mostly seen in middle-aged patients. TGCT is usually not visible on radiographs and MRI is mostly used to enable assessment of potential bone involvement and distinguishing between two TGCT types. Localised TGCT is mostly treated with marginal surgical resection, while diffuse TGCT is optimally treated with total synovectomy and is more difficult to remove. Additionally, radiotherapy, intraarticular injection of radioactive isotopes, anti-TNF-α antibodies and targeted medications may be used.

Diaphyseal giant cell tumor with multiple relapses in a skeletally immature patient: a case report

Giant cell tumor (GCT) is an aggressive osteolytic lesion mostly affecting the meta-epiphyses of long bones at skeletal maturity. Occurrence of the GCT in diaphysis is a rare entity in adult and exceptionally rare in pediatric population. This is the only third diaphyseal case reported in pediatric population. We report a case of recurrent diaphyseal GCT in a skeletally immature patient of 15-year-old male at the right radius after previous resection with plate and screw fixation. Upon optimal investigations, en-bloc resection of the tumor with radial resection and ulna centralization with wrist arthrodesis was done for a campanacci stage III GCT. The patient had an uneventful recovery without recurrence for 2 years and 2 months following surgery. The main challenge relies on accurate diagnosis due to uncommon location that hinders adequate treatment plan, therefore diagnosis should be solely based on histopathology findings.

Update on aneurysmal bone cyst: pathophysiology, histology, imaging and treatment

Aneurysmal bone cyst (ABC) is a benign but locally aggressive lesion that predominantly affects children and young adults. ABC, which accounts for approximately 70% of the cases, is now recognized to be a true neoplasm, whereas ABC-like changes associated to other bone neoplasms (also referred in the literature as secondary ABC) accounts for the remaining 30%. The solid variant of ABC is also considered a true neoplasm but is rare. ABC can involve any bone in the body, and although it has a metaphyseal preference, it can involve any part of a bone and soft tissues. As with any bone tumor, the initial evaluation of ABCs should be done with radiographs followed by magnetic resonance imaging or less frequently computed tomography for further characterization. The imaging appearance of ABC is variable; however, a lytic and expansile lesion with fluid-fluid levels is the most common presentation. The main differential diagnosis of an ABC in the pediatric population is unicameral bone cyst (UBC) and telangiectatic osteosarcoma, therefore a biopsy is recommended before treatment. The therapeutic options of ABC range from curettage with or without adjuncts such as phenol, liquid nitrogen, argon laser and bone grafting or bone substitutes to more recently employed alternatives such as image-guided sclerotherapy with various sclerosing agents and monoclonal antibodies (e.g., Denosumab).

Mechanisms of acute hypercalcemia in pediatric patients following the interruption of Denosumab

PURPOSE

Denosumab is a fully human monoclonal anti-RANK-L antibody that is clinically used to counteract the bone loss induced by exacerbated osteoclast activity. Indeed, its binding to RANK-L prevents the interaction RANK-L/receptor RANK that is essential for osteoclastogenesis and bone resorbing activity. Although there are many medications available to treat bone loss diseases, including bisphosphonates, Denosumab is highly effective since it reduces the bone erosion. The use in pediatric patients is safe. However, some concerns are related to the interruption of the treatment. Indeed, in this study, we reported hypercalcemia in two pediatric patients and alterations of circulating osteoclast precursors.

METHODS

Peripheral Blood Mononuclear Cells (PBMC) were isolated from two pediatric patients with hypercalcemia after Denosumab interruption and from 10 controls. Cytofluorimetric analysis and in vitro osteoclastogenesis experiments were performed.

RESULTS

Increase of CD16^-CD14⁺CD11b⁺ cells was revealed in PBMC from patients reflecting the enhanced in vitro osteoclastogenesis.

CONCLUSION

Our data suggest that precautions must be taken when Denosumab therapy is interrupted and gradual decrease of dose and/or timing of treatment should be performed. To prevent the onset of hypercalcemia that could be in the discontinuation phase, cytofluorimetric analysis of PBMC should be performed to evaluate osteoclast precursors.

LONG-TERM USE OF DENOSUMAB IN GIANT CELL TUMORS AND VERTEBRAL ANEURYSMAL BONE CYSTS

ABSTRACT Introduction: Denosumab is a human monoclonal antibody that binds to the receptor activator of nuclear factor kB (RANKL), it is used in the treatment of Osteoporosis. The Giant Cell Tumor (GCT) and the Aneurysmal Bone Cyst (ABC) use the same RANKL, and for this reason this drug began to be used for its treatment. There is consensus on the use, dose-time and 12-month duration for Denosumab treatment of GCT. Not so for ABC. In unresectable, disabling or recurrent tumors, its use could be for life. The adverse events of the habitual use of the drug are known, but it is not known if these increase with time. The objective of the present work is to identify the possible adverse events of treatment with Denosumab for more than 12 months. Material and Method: Series of cases with a diagnosis of GCT or ABC in spine, treated with Denosumab for more than 12 months. Adverse events are: arthralgia, fatigue, spinal pain, pain in extremities, headache, hypokalaemia, hypocalcemia, osteonecrosis of the jaw, malignant transformation, pathological fractures. Results: Eight patients, 6 TCG and 2 ABC, with a mean age at diagnosis of 25,6 years; presenting a mean treatment of 4.18 years (range 1.7 - 8.7). Of 6 operated patients, 4 had recurrence (2 to 36 months after surgery). One patient had to suspend treatment due to necrosis of the jaw, another hypocalcemia, both returned to treatment when stabilized. Conclusions: A minor adverse event (hypocalcemia) and a major adverse event (jaw bone necrosis) were observed. Level of Evidence IV; Original.

OUP accepted manuscript

Background

Methods

Results

Conclusions

Single-Cell RNA Sequencing Reveals the Migration of Osteoclasts in Giant Cell Tumor of Bone

Giant cell tumor of bone (GCTB) is benign tumor that can cause significant osteolysis and bone destruction at the epiphysis of long bones. Osteoclasts are thought to be highly associated with osteolysis in GCTB. However, the migration of osteoclasts in GCTB remains unclear. A deeper understanding of the complex tumor microenvironment is required in order to delineate the migration of osteoclasts in GCTB. In this study, samples were isolated from one patient diagnosed with GCTB. Single-cell RNA sequencing (scRNA-seq) was used to detect the heterogeneity of GCTB. Multiplex immunofluorescence staining was used to evaluate the cell subtypes identified by scRNA-seq. A total of 8,033 cells were obtained from one patient diagnosed with GCTB, which were divided into eight major cell types as depicted by a single-cell transcriptional map. The osteoclasts were divided into three subsets, and their differentiation trajectory and migration status were further analyzed. Osteoclast migration may be regulated via a series of genes associated with cell migration. Furthermore, four signaling pathways (RANKL, PARs, CD137 and SMEA3 signaling pathway) were found to be highly associated with osteoclast migration. This comprehensive single-cell transcriptome analysis of GCTB identified a series of genes associated with cell migration as well as four major signaling pathways that were highly related to the migration of osteoclasts in GCTB. Our findings broaden the understanding of GCTB bionetworks and provides a theoretical basis for anti-osteolysis therapy against GCTB in the future.

Establishment and characterization of novel patient-derived cell lines from giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a locally aggressive and rarely metastasizing tumor. GCTB is characterized by the presence of unique giant cells and a recurrent mutation in the histone tail of the histone variant H3.3, which is encoded by H3F3A on chromosome 1. GCTB accounts for ~ 5% of primary bone tumors. Although GCTB exhibits an indolent course, it has the potential to develop aggressive behaviors associated with local recurrence and distant metastasis. Currently, complete surgical resection is the only curative treatment, and novel therapeutic strategies are required. Patient-derived cancer cell lines are critical tools for basic and pre-clinical research. However, only a few GCTB cell lines have been reported, and none of them are available from public cell banks. Therefore, we aimed to establish novel GCTB cell lines in the present study. Using curetted tumor tissues of GCTB, we established two cell lines and named them NCC-GCTB2-C1 and NCC-GCTB3-C1. These cells harbored a typical mutation in histones and exhibited slow but constant growth, formed spheroids, and had invasive capabilities. We demonstrated the utility of these cell lines for high-throughput drug screening using 214 anticancer agents. We concluded that NCC-GCTB2-C1 and NCC-GCTB3-C1 cell lines were useful for the in vitro study of GCTB.

Personalized medicine modality based on patient-derived xenografts from a malignant transformed GCTB harboring H3F3A G34W mutation

Background

The function of H3F3A G43W mutation, which has been observed in almost all GCTB, remains poorly characterized. Breakthrough in malignant GCTB has been trapped by the lack of clinical available drugs, limited canonical patient samples and paucity of fidelity preclinical models.

Methods

Tumor samples obtained from a malignant GCTB was implanted in immunodeficient mice for the generation of PDX. Histological examination and short tandem repeat (STR) were used for inherited features analyses. An epigenetic/transcriptional targeted compound library was selected for drug screening. The in vivo effects of selected drug were validated in PDX model.

Results

We established the PDX model with recurrent malignant GCTB specimens, histological examination and STR analyses revealed that PDX and their corresponding parental patients shared the same STRs and histologic features, suggesting common origins. ITF-2357 was the most significant compound with an IC50 lower than 0.1 uM. The results of the drug screening and in vivo PDX validation demonstrated that ITF-2357 might be a promising drug targeted H3F3A G34W mutation MGCTBs.

Conclusion

Our study demonstrates that PDX model maintained the same histologic and genetic features as those in the original patient. targeting HDAC through ITF-2357 effectively overcomes malignant GCTB progression in vitro and in vivo.

Translational potential statement

As PDX retain the principal histologic and genetic characteristics of the primary tumors, mad it a valuable research tool in predictive clinical efficacy. In this study, we first established a malignant GCTB PDX model, which might further accelerate the progress of drug development in malignant GCTB.

Role of denosumab before resection and reconstruction in giant cell tumors of bone: a single-centered retrospective cohort study

BACKGROUND

Denosumab has been approved by Food and Drug Authority in 2013 for use in surgically unresectable Giant cell tumor (GCT) to achieve resectable tumor margins. The aim of this study is to investigate the functional outcome and surgical convenience with the use of neoadjuvant denosumab before resection and reconstruction in Campanacci grade III GCT.

METHODS

We retrospectively reviewed 70 cases of Campanacci grade III GCT receiving resection and reconstruction between January 2014 and December 2019. They were stratified into two groups: one group of 29 patients received once-weekly denosumab 120 mg for 4-weeks before resection and reconstruction, while the other group of 41 patients did not receive denosumab before resection and reconstruction. Quality of life by musculoskeletal tumor society score where 0-7 means poor, 8-14 means fair, 15-22 means good; above 22 means excellent, incidence of tumor recurrence, intraoperative duration in minutes and postoperative positive margins were assessed for each cohort after 12 months follow-up.

RESULTS

There was no significant difference in musculoskeletal tumor society score (25.75 vs. 27.41; P  = 0.178), incidence of recurrence (3.45% vs. 4.88%; P  < 0.001), and postoperative positive margins (10.34% vs. 4.88%; P  = 0.38) for both groups. However, the intraoperative duration (133.38 vs. 194.49; P  < 0.001) was significantly higher in the non-denosumab group compared with denosumab group.

CONCLUSIONS

Neoadjuvant denosumab is equally effective considering postoperative functional outcomes and surgical convenience except intraoperative duration where it is highly helpful in saving the operating time duration. Easier identification, resection and lesser reconstruction are the key surgical convenience offered by neoadjuvant denosumab.

Anti-IL17 antibody Secukinumab therapy is associated with ossification in giant cell tumor of bone: a case report of pathologic similarities and therapeutic potential similar to Denosumab

Background

Giant cell tumor of bone is a benign, locally aggressive neoplasm. Surgical resection is the preferred treatment method. However, for cases in which resection poses an increased risk to the patient, denosumab (anti-RANKL monoclonal antibody) is considered. Secukinumab is an anti-IL-17 antibody that is used in psoriatic arthritis to reduce bone resorption and articular damage.

Case presentation

One case of giant cell tumor of bone (GCTB) in a patient treated with secukinumab for psoriatic arthritis demonstrated findings significant for intra-lesional calcifications. Histologic examination showed ossification, new bone formation, and remodeling. A paucity of osteoclast type giant cells was noted. Real-time quantitative polymerase-chain-reaction (qRT-PCR) analysis revealed decreased osteoclast function compared to treatment-naive GCTB.

Conclusions

Secukinumab may play a role in bone remodeling for GCTB. Radiologists, surgeons, and pathologists should be aware of this interaction, which can cause lesional ossification. Further research is required to define the therapeutic potential of this drug for GCTB and osteolytic disease.

Successful denosumab treatment for central giant cell granuloma in a 9-year-old child

BACKGROUND

Denosumab is a nonsurgical treatment option for central giant cell granulomas (CGCG), especially in aggressive lesions.

CASE REPORT

We describe a 9-year-old girl with an aggressive maxillary CGCG successfully treated with denosumab, avoiding a mutilating surgery after intralesional corticosteroid injections failed, and the lesion continued to rapidly grow. During denosumab treatment, she developed a self-limiting area of osteonecrosis in the maxillary alveolar bone, which rapidly resolved after antibiotic therapy. Six months after denosumab discontinuation, a maxillary surgical recontour was performed. Two weeks after surgery, the patient presented vomiting, pallor, dehydration, but no fever. Blood tests revealed severe hypercalcemia and acute renal dysfunction. After discarding thyroid, parathyroid, and adrenal alterations, a diagnosis of severe rebound hypercalcemia after denosumab treatment was made. Treatment consisted of hyperhydration, calcium pamidronate, and methylprednisolone, restoring calcium levels to normal.

CONCLUSION

After 2 years of follow-up, she remains on orthodontic treatment, with no recurrences or other episodes of hypercalcemia.

Treatment of central giant cell granuloma in children with denosumab

Central giant cell granuloma (CGCG) is a benign but locally aggressive intraosseous lesion of the mandible. Historically, it is treated by curettage or resection. Medical therapy is indicated when surgery is associated with increased morbidity or in adjuvant setting to decrease recurrence. Treatment of CGCG with denosumab, a receptor activator of nuclear factor kappa-beta (RANK) ligand inhibitor, is not well studied, especially in children. Here, we describe our experience with the use of denosumab in the treatment of six children with CGCG. All patients had a favorable response with manageable side effects, which suggests that denosumab is an effective treatment option without increased morbidity.

Prognostic Factors for Survival in Patients with Malignant Giant Cell Tumor of Bone: A Risk Nomogram Analysis Based on the Population

Background

Malignant giant cell tumor of bone (MGCTB) is a rare histological type of malignant tumor that has a high tendency for local relapse and distant metastasis and ultimately leads to a poor prognosis. The purpose of this study was to describe the epidemiological features, identify the prognostic factors, and construct nomograms for patients with MGCTB.

Material/Methods

Patients with MGCTB that was histologically diagnosed between 1973 and 2014 were selected from the Surveillance, Epidemiology, and End Results (SEER) database as a training set. Survival analysis, Lasso regression, and random forests were used to identify the prognostic variables and establish the nomograms for patients with MGCTB, while an external cohort of 37 patients from our own institution and an external cohort of 163 patients from the SEER database in 2016 were used to validate the generalization performance of the nomograms.

Results

In total, univariate and multivariable analysis indicated that age, International Classification of Diseases for Oncology, historical stage, primary site, surgery information, radiotherapy, and chemotherapy were independent prognostic variables for overall survival or cause-specific survival. Nomograms based on the multivariable models were built to predict survival, and we achieved a higher C-index in subsequent multidimensional validation.

Conclusions

Age, historical stage, and chemotherapy were independent prognostic variables for overall survival and cause-specific survival of MGCTB patients, and radiotherapy and primary site were independent prognostic variables for overall survival. Nomograms based on significant clinicopathological features and clinical experience can be effective in predicting the probability of survival for MGCTB patients.

The use of denosumab in the setting of acute pathological fracture through giant cell tumour of bone

Background

Denosumab (Xgeva^TM) is a fully human antibody to RANK-Ligand, an important signal mediator in the pathogenesis of giant cell tumour of bone (GCTB). The use of denosumab in the treatment of GCTB has changed the way in which these tumours are managed over the past years.

Case presentation

Described is the case of an acute fracture through a GCTB of the distal radius of a fit and well 32-year-old, non-smoking, female patient following a simple fall onto her outstretched, dominant hand. The aim was to enable joint sparing management for the patient, as opposed to an acute fusion procedure of the carpus. The patient underwent percutaneous k-wire fixation with application of plaster and immediate commencement with denosumab to halt the activity of the GCTB. Bone healing was rapid; plaster and k-wires were removed after 6 weeks. At 6 months denosumab, was ceased and an open curettage and grafting procedure of the tumour bed was undertaken (using MIIG X3, Wright Medical, aqueous calcium sulphate as graft material).

Conclusions

The use of denosumab in the acute setting of pathological fracture through giant cell tumour of bone allowing joint salvage has not been previously described. The treatment was well tolerated and functional outcomes are excellent, with very promising 4-year follow-up.

This novel approach may allow for more joint sparing strategies in the future for other patients in this difficult situation. Further cases will need to be gathered to establish this technique as a suitable treatment pathway.

CD301 mediates fusion in IL-4-driven multinucleated giant cell formation

Multinucleated giant cells (MGCs) are prominent in foreign body granulomas, infectious and inflammatory processes, and auto-immune, neoplastic and genetic disorders, but the molecular determinants that specify the formation and function of these cells are not defined. Here, using tandem mass tag-mass spectrometry, we identified a differentially upregulated protein, C-type lectin domain family 10 member (herein denoted CD301, also known as CLEC10A), that was strongly upregulated in mouse RAW264.7 macrophages and primary murine macrophages undergoing interleukin (IL-4)-induced MGC formation. CD301⁺ MGCs were identified in biopsy specimens of human inflammatory lesions. Function-inhibiting CD301 antibodies or CRISPR/Cas9 deletion of the two mouse CD301 genes (Mgl1 and Mgl2) inhibited IL-4-induced binding of N-acetylgalactosamine-coated beads by 4-fold and reduced MGC formation by 2.3-fold (P<0.05). IL-4-driven fusion and MGC formation were restored by re-expression of CD301 in the knockout cells. We conclude that in monocytes, IL-4 increases CD301 expression, which mediates intercellular adhesion and fusion processes that are required for the formation of MGCs.This article has an associated First Person interview with the first author of the paper.

Current concepts in the treatment of giant cell tumour of bone

PURPOSE OF REVIEW

Giant cell tumour of bone (GCTB) is an intermediate, locally aggressive primary bone tumour. In addition to local therapy, new drugs became available for this disease. Denosumab, a receptor activator of nuclear factor κ-B-ligand inhibitor, was introduced as systemic targeted therapy for advanced or inoperable and metastatic GCTB. Also, the bisphosphonate zoledronic acid has activity in GCTB by directly targeting the neoplastic stromal cells.

RECENT FINDINGS

In a small RCT, bisphosphonates were successful in controlling tumour growth and a higher apoptotic index of tumour cells was seen after zoledronic acid versus controls. Although bisphosphonate-loaded bone cement has not been studied to a large extent, it does not seem harmful and may constitute a logical local adjuvant. From the largest clinical trial to date, the risk-to-benefit ratio for denosumab in patients with advanced GCTB remains favourable, also in facilitating less morbid surgery. Concerns have arisen that recurrence rates would be higher than after conventional treatment, ranging from 20 to 100% in a systematic review, although this may be because of bias. H3F3A (G34W) driver mutations are helpful in the differentiation between GCTB and other giant cell-containing malignancies. H3.3-G34W proved sufficient to drive tumourigenesis. The cumulative incidence of malignancy in GCTB is estimated at 4%, of which primary malignancy 1.6% and secondary malignancy 2.4%, the latter mainly after radiation. To date, a potential causal relationship between denosumab and pulmonary metastases has not been confirmed; if they do not behave indolently, it would be advised to reassess diagnosis and consider malignancy.

SUMMARY

Denosumab remains a highly effective treatment option for patients with advanced GCTB. A short duration of 2-4 months neoadjuvant denosumab is advised to facilitate less morbid surgery and prevent incomplete curettage by macroscopic tumour alterations. Reduced dose intensity is being studied to reduce long term side-effects. Further research on bisphosphonates and other targets including H3.3-G34W remains warranted.

Adjuvant Alendronic Acid in the Management of Severe Cherubism: A Case Report and Literature Review

Cherubism is a rare disease of the jaws characterized by bilateral symmetrical painless expansion of the mandible and maxilla. In extreme cases, larger lesions can become exophytic and have profound functional and esthetic implications. Several pharmacologic agents have been trialed in the treatment of cherubism with variable success reported. Bisphosphonates have not been significantly studied in this setting. We present a case where oral alendronic acid was used as an adjuvant treatment after surgical debulking of the maxilla in a 13-year-old boy with a severe case of cherubism.

p62 overexpression promotes neoplastic stromal cell proliferation and is associated with the recurrence of giant cell tumor of bone

Giant cell tumor of bone (GCTB) is an intermediate (locally aggressive) bone tumor with a recurrence rate of >30% following surgery. GCTB recurrence is ultimately due to the proliferation of neoplastic stromal (NS) cells. However, the precise mechanism underlying the regulation of NS cell proliferation remains unknown. p62 protein is a multifunctional adaptor protein that exerts a positive role in bone tumors and metabolic bone diseases. In the present study, the mRNA and protein expression levels of p62 were detected by reverse transcription-quantitative PCR and western blotting, respectively, in 8 paired fresh GCTB tumor tissues and adjacent normal cancellous bone tissues. The association between p62 expression level and patient prognosis was subsequently analyzed in 54 paraffin-embedded tumor specimens by immunohistochemistry assay. NS cells were isolated from GCTB primary cell culture, and the role of p62 was evaluated using in vitro cell proliferation, migration and invasion assays. The results revealed that p62 mRNA and protein were overexpressed in tumor tissues. High p62 expression levels were significantly associated with the recurrence of GCTB (P=0.001). The patients in the high p62 expression group had shorter 5-year recurrence-free survival rates compared with the patients in the low p62 expression group (P<0.001). Cox regression analysis identified p62 expression as an independent prognostic indicator of the recurrence-free survival of patients with GCTB (P<0.001). The in vitro experiments revealed that p62 downregulation inhibited NS cell proliferation, invasion and migration, and promoted apoptosis. In conclusion, it was found that p62 overexpression is associated with the recurrence of GCTB via the promotion of NS cell proliferation. Therefore, p62 could be a novel prognostic indicator, and a potential therapeutic target for GCTB.

When primary hyperparathyroidism comes as good news

SUMMARY

Brown tumors are osteoclastic, benign lesions characterized by fibrotic stroma, intense vascularization and multinucleated giant cells. They are the terminal expression of the bone remodelling process occurring in advanced hyperparathyroidism. Nowadays, due to earlier diagnosis, primary hyperparathyroidism keeps few of the classical manifestations and brown tumors are definitely unexpected. Thus, it may happen that they are misdiagnosed as primary or metastatic bone cancer. Besides bone imaging, endocrine evaluation including measurement of serum parathyroid hormone and calcium (Ca) levels supports the pathologist to address the diagnosis. Herein, a case of multiple large brown tumors misdiagnosed as a non-treatable osteosarcoma is described, with special regards to diagnostic work-up. After selective parathyroidectomy, treatment with denosumab was initiated and a regular follow-up was established. The central role of multidisciplinary approach involving pathologist, endocrinologist and oncologist in the diagnostic and therapeutic work-up is reported. In our opinion, the discussion of this case would be functional especially for clinicians and pathologists not used to the differential diagnosis in uncommon bone disorders.

LEARNING POINTS

Brown tumors develop during the remodelling process of bone in advanced and long-lasting primary or secondary hyperparathyroidism. Although rare, they should be considered during the challenging diagnostic work-up of giant cell lesions. Coexistence of high parathyroid hormone levels and hypercalcemia in primary hyperparathyroidism is crucial for the diagnosis. A detailed imaging study includes bone X-ray, bone scintiscan and total body CT; to rule out bone malignancy, evaluation of bone lesion biopsy should include immunostaining for neoplastic markers as H3G34W and Ki67 index. If primary hyperparathyroidism is confirmed, selective parathyroidectomy is the first-line treatment. In advanced bone disease, treatment with denosumab should be considered, ensuring a strict control of Ca levels.

Fibrous Dysplasia/McCune-Albright Syndrome: A Rare, Mosaic Disease of Gα s Activation

Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare disorder of striking complexity. It arises from somatic, gain-of-function mutations in GNAS, leading to mosaic Gα s activation and inappropriate production of intracellular cyclic adenosine monophosphate (cAMP). The clinical phenotype is largely determined by the location and extent of affected tissues, and the pathophysiological effects of Gα s activation within these tissues. In bone, Gα s activation results in impaired differentiation of skeletal stem cells, leading to discrete skeletal lesions prone to fracture, deformity, and pain. Extraskeletal manifestations include a variable combination of hyperpigmented macules and hyperfunctioning endocrinopathies. Distinctive age-related changes in disease development has key effects on histologic, radiographic, and clinical features. FD/MAS thus presents along a uniquely broad clinical spectrum, and the resulting challenges in diagnosis and management can be difficult for clinicians. This review presents FD/MAS in the context of a mosaic disorder of Gα s activation, providing an intellectual framework within which to understand, evaluate, and treat this interesting disease. It includes a comprehensive summary of current understanding of FD/MAS pathogenesis, and a detailed discussion of clinical presentation and management. Critical areas of unmet need are highlighted, including discussion of key challenges and potential solutions to advance research and clinical care in FD/MAS.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.