Modern interpretation of giant cell tumor of bone: predominantly osteoclastogenic stromal tumor

Molecular pathological insights into tumorigenesis and progression of giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a primary bone tumor that typically exhibits benign histological appearance and clinical behavior in most cases, with local aggressiveness and rare metastasis. It predominantly affects individuals in the young adult age group. It is characterized by the presence of multinucleated osteoclastic giant cells and a stromal population of neoplastic cells. A key hallmark for GCTB pathogenesis is the G34W genetic mutation in the histone H3.3 gene, which is restricted to the population of cancerous stromal cells and is absent in osteoclasts and their progenitor cells. This review presents a comprehensive overview of the pathology of GCTB, including its histopathological characteristics, cytological features, histopathological variants, and their clinical relevance. We also discuss recent insights into genetic alterations in relation to the molecular pathways implicated in GCTB. A summary of the current understanding of GCTB pathology will update the knowledge base to guide the diagnosis and management of this unique bone tumor.

Immunohistochemical Characterization of Feline Giant Cell Tumor of Bone (GCTb): What We Know and What We Can Learn from the Human Counterpart

Giant cell tumor of bone (GCTb), formerly also known as osteoclastoma, is a pathological entity that in veterinary medicine is still undefined and, probably, underdiagnosed. In humans, GCTb is recognized as a primary benign bone tumor, locally aggressive, with high local recurrence rates, with controversial histogenesis that can rarely progress or present as a malignant form. In pets, this tumor is still considered rare, though the possibility of underdiagnosis is significant. Hence, the aim of the present study is to provide a histological and immunohistochemical characterization of a small case series of presumptive feline GCTb, comparing our results to the data reported for the human counterpart. Searching our archive, we found, from 2010 to 2023, only three diagnosed cases of GCTb from domestic cats (felis catus). After diagnosis revision, the samples were submitted to immunohistochemistry for Iba1, TRAP, SATB2, RUNX2, RANK, karyopherin α2 (KPNA-2), and osteocalcin. Ki-67 index was also evaluated. Results showed that the multinucleated giant cells were positive for Iba1, TRAP, and RANK, accounting for their osteoclastic origin. On the other side, mononuclear cells were mostly positive for osteoblast markers such as RUNX2, SATB2, and KPNA-2, whereas tumor-associated macrophages showed positivity for Iba1. Hence, results on the cell types characterizing the feline GCTb were comparable to those described in the human form of the tumor. Currently, diagnostic criteria for GCTBs in cats and, in domestic animals more broadly, are still lacking. This study provides valuable data into the immunohistochemical characteristics of the cell populations in feline GCTBs, enhancing veterinarians' and pathologists' knowledge for its diagnosis, ultimately improving patient care. Larger case series, complete with follow-up information, molecular analyses for specific mutations, and imaging of both tumors and patients, are needed to improve identification and achieve greater sensitivity in diagnosing this unique tumor.

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.

[Giant cell tumor of bone-an update]

In the past few years, numerous new insights have been gained in the field of giant cell tumor of bone (GCTB). On the one hand, the detection of the highly characteristic histone mutation in the H3F3A gene in GCTB is becoming increasingly important in diagnostics in differentiating GCTB from other giant cell-rich lesions of bone as well as for defining rare variants of GCTB without osteoclastic giant cells. On the other hand, the effects of the H3F3A mutation were shown to have an impact on the epigenetic profile of tumor-driving stromal cells, providing new insights into tumorigenesis of GCTB.

Why Animal Experiments Are Still Indispensable in Bone Research: A Statement by the European Calcified Tissue Society

Major achievements in bone research have always relied on animal models and in vitro systems derived from patient and animal material. However, the use of animals in research has drawn intense ethical debate and the complete abolition of animal experimentation is demanded by fractions of the population. This phenomenon is enhanced by the reproducibility crisis in science and the advance of in vitro and in silico techniques. 3D culture, organ-on-a-chip, and computer models have improved enormously over the last few years. Nevertheless, the overall complexity of bone tissue cross-talk and the systemic and local regulation of bone physiology can often only be addressed in entire vertebrates. Powerful genetic methods such as conditional mutagenesis, lineage tracing, and modeling of the diseases enhanced the understanding of the entire skeletal system. In this review endorsed by the European Calcified Tissue Society (ECTS), a working group of investigators from Europe and the US provides an overview of the strengths and limitations of experimental animal models, including rodents, fish, and large animals, as well the potential and shortcomings of in vitro and in silico technologies in skeletal research. We propose that the proper combination of the right animal model for a specific hypothesis and state-of-the-art in vitro and/or in silico technology is essential to solving remaining important questions in bone research. This is crucial for executing most efficiently the 3R principles to reduce, refine, and replace animal experimentation, for enhancing our knowledge of skeletal biology, and for the treatment of bone diseases that affect a large part of society. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Current therapies and future prospective for locally aggressive mesenchymal tumors

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients' quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient's clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aim to discuss the biology, clinical management, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs.

A Comparative Clinicopathological Study of Giant Cell Tumour (GCT), Central Giant Cell Granuloma (CGCG) and Peripheral Giant Cell Granuloma (PGCG)

Objective

To evaluate and compare the clinicopathological features of giant cell tumour (GCT), central giant cell granuloma (CGCG) and peripheral giant cell granuloma (PGCG).

Material and methods

From 2006 to 2016, all histopathologically diagnosed cases of GCT were retrieved from the Department of Pathology, T.N.M.C, Mumbai and CGCG and PGCG were retrieved from the Department of Oral Pathology, Nair Hospital Dental College, Mumbai. Statistical analysis of the clinicopathological features was done using SPSS v 21.0, IBM. Intergroup comparison of all variables was done using t test for two groups, whereas, Kruskal-Wallis test and one-way ANOVA were done for more than two groups.

Results

Twelve cases of GCT, 31 cases of CGCG and 39 cases of PGCG were reported over 11 years. The mean age of occurrence for GCT, CGCG and PGCG was 30.41 years, 27.69 years and 34.03 years, respectively. GCT was seen in long bones and CGCG and PGCG showed mandible predilection. Histologically, GCT showed evenly distributed giant cells with aggregated nuclei, whereas CGCG and PGCG showed aggregated giant cells with evenly distributed nuclei. The mean value of the number of giant cells and nuclei within giant cells was maximum in GCT (27.33, 33.50) followed by CGCG (23.56, 15.51) and PGCG (21.45, 11.32).

Conclusion

The clinicopathological differences between GCT, CGCG and PGCG suggest that each one of these entities represent biologically different lesions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12663-022-01724-3.

Significance of Histone H3.3 (G34W)-Mutant Protein in Pathological Diagnosis of Giant Cell Tumor of Bone

OBJECTIVE

This study aimed to examine the expression of Histone H3.3 glycine 34 to tryptophan (G34W) mutant protein in Giant Cell Tumor of Bone (GCTB).

METHODS

This analytic observation research used a cross-sectional study design on 71 bone tumors. The cases involved 54 tissue samples diagnosed as GCBT. It was divided into GCTB primer (n=37), recurrent GCTB (n=5), GCTB with metastasis (n=9), and malignant GCTB (n=3). There were 17 samples mimics of GCTB also tested, including chondroblastoma (n=1), giant cell reparative granuloma (n=2), giant cell of tendon sheath (n=7), chondromyxoid fibroma (n=2), aneurysmal bone cyst (n=2), and giant cell-rich osteosarcoma (n=3). The Immunohistochemistry was used to evaluate the expression of G34W-mutated protein in these bone tumors.

RESULT

The representation H3.3 (G34W) was expressed in the nuclei of mononuclear stromal cells but not stained on osteoclast-like giant cells. This study was analyzed by the Chi-square test, Fisher's test, specificity test, and sensitivity test. We obtained p = 0.001 for Histone H3.3 (G34W) mutant expression in GCTB vs Non-GCTB. Statistically, there was no significant difference in the expression level of Histone H3.3 (G34W) in the GCTB and its variants p-value = 0.183. We also obtained that the specificity of Histone H3.3 expression on GCTB was 100% and the sensitivity of Histone H3.3 on GCTB was 77.8%.

CONCLUSION

Histon H3.3 mutant as a mutated driver gene in an Indonesian GCTB can assist to diagnose GCTB and compare it from other bone tumors.

Premalignant Conditions of Bone

Development of malignancy is a multifactorial process, and there are multitude of conditions of bone that may predispose patients to malignancy. Etiologies of malignancy include benign osseous conditions, genetic predisposition, and extrinsic conditions. New-onset pain or growth in a previously stable lesion is that should concern for malignant change and should prompt a diagnostic workup for malignancy.

Secondary Malignancy in Giant Cell Tumor: A Single-Center Study

Giant cell tumor of bone (GCTB) undergoes a sarcomatous transformation. Secondary malignancy in giant cell tumor (MGCT) is associated with radiotherapy and has a dismal prognosis. We reviewed medical records to investigate the clinicopathological characteristics and prognosis of MGCT patients. The enrollment criterion was high-grade spindle-cell sarcoma, which developed at the site of prior GCTB treatment. Twelve patients were analyzed: six females and six males. The median age was 42.5 years. Benign recurrence occurred in five GCTB patients not treated with radiotherapy. No pulmonary implants were observed. The median latency to the malignant transformation was 63 months. Nine patients were AJCC stage IIB, and three were stage IVA. The median follow-up period after malignant transformation was 62.5 months. Five patients developed local recurrence, and six had distant metastasis. Five-year overall recurrence and metastasis-free survival rates were 61.9%, 66.7%, and 58.3%, respectively. Initial metastasis was a predictive factor for overall survival. Benign local recurrence of GCTB was also a negative factor for metastasis-free survival of MGCT patients. Differences in overall survival according to benign recurrence also showed a tendency toward significance. In our series, secondary MGCT did not occur after radiotherapy. The prognosis was better than previous findings. Benign recurrence of GCTB could reflect the prognosis of MGCT.

Characteristics of Giant Cell Tumor of the Bone in Pediatric Patients: Our 18-Year, Single-Center Experience

A giant cell tumor (GCT) of the bone is characteristically found in skeletally mature patients. The tumor is rare in pediatric patients, and incidence reported in literature varies from 1.8% to 10.6%. We performed a retrospective study addressing symptoms, treatment, and outcome in pediatric patients who were diagnosed with GCT between March 1997 and January 2015 at our hospital. Fourteen (11.1%) of 126 surgically treated patients with histologically proven GCT were <19 years of age. We confirmed skeletal maturity using magnetic resonance imaging (MRI). Fourteen patients from 8 to 19 years old were identified. Sixteen lesions (76.2%) were found in long bones and 5 lesions (23.8%) in short bones. The most common site was around the knee in 8 patients (38%). GCTs mostly occur at the epi-metaphysis in 11 patients (52.3%). Regardless of the openness of epiphyseal plate, we observed GCT of bone in the epiphysis. Further study will be needed to prove the association between the presence of epiphyseal plate and location of tumor. Three patients (21.4%) had multicentric lesions, and four patients (28.5%) had local recurrence. Multicentric giant cell tumor and local recurrence occur more often in pediatric patients. The characteristics of GCT in pediatric patients do not differ from what is reported for GCT in adults.

Stromal cells of giant cell tumor of bone show primary cilia in giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone neoplasm composed by tumoral stromal cells (SCs) and a reactive component that consists of monocytic/histiocytic cells that give rise by fusion to osteoclast-like multinucleated cells. Recently, specific Histone 3.3 mutations have been demonstrated in SCs of GCTB. Many of the pathways related to bone proliferation and regulation depend on the primary cilium, a microtubule-based organelle that protrudes outside the cell and acts as a sensorial antenna. In the present work, we aimed to study the presence and role of primary cilia in GCTB. Ultrastructural, immunohistochemical, and immunofluorescence studies were performed in order to demonstrate, for the first time, that the primary cilium is located in spindle-shaped SCs of GCTB. Moreover, we showed Hedgehog (Hh) signaling pathway activation in these cells. Hence, primary cilia may play a relevant role in GCTB tumorogenesis through Hh signaling activation in SCs. RESEARCH HIGHLIGHTS: Transmission electron microscopy allows describing and differentiating cellular subpopulations in giant cell tumor of bone (GCTB). The primary cilium is present in some tumoral stromal cells of GCTB. Hedgehog signalling is activated in these cells.

Osteoclasts in Tumor Biology: Metastasis and Epithelial-Mesenchymal-Myeloid Transition

Osteoclast is a specialized cell that originates from monocytic lineage, communicates closely with osteoblasts under physiological conditions, participates in bone modeling and re-modeling, contributes to calcium homeostasis and osteoimmunity. In pathological conditions, it is involved in many tumors such as giant cell bone tumor (osteoclastoma), aneurysmal bone cyst, osteosarcoma, and metastatic cancers, and it usually causes local spread and progression of the tumor, working against the host. Since osteoclasts play an active role in primary bone tumors and bone metastases, the use of anti-osteoclastic agents significantly reduces the mortality and morbidity rates of patients by preventing the progression and local spread of tumors. Osteoclasts also accompany undifferentiated carcinomas of many organs, especially pancreas, thyroid, bladder and ovary. Undifferentiated carcinomas rich in osteoclasts have osteoclastoma-like histology. In these organs, osteoclastoma-like histology may accompany epithelial carcinomas, and de novo, benign and borderline tumors. Mature and immature myeloid cells, including osteoclasts, play an active role in the tumor progression in primary and metastatic tumor microenvironment, in epithelial-mesenchymal transition (EMT), mesenchymal-epithelial-transition (MET), and cancer stem cell formation. Additionally, they are the most suitable candidates for cancer cells in cell fusion due to their evolutionary fusion capabilities. Myeloid features and markers (CD163, CD33, CD68 etc.) can be seen in metastatic cancer cells. Consequently, they provide metastatic cancer cells with motility, margination, transmigration, chemotaxis, phagocytosis, angiogenesis, matrix degradation, and resistance to chemotherapy. For these reasons, we think that the concept of Epithelial-Mesencyhmal-Myeloid-Transition (EMMT) will be more accurate than EMT for cancer cells with myeloid properties.

Acute respiratory failure as initial manifestation of conventional osteosarcoma rich in giant cells: a case report

Background

Osteosarcoma is a malignant tumor of the bone. The giant cell-rich osteosarcoma (GCRO) is a rare histological variant of the conventional osteosarcoma, accounting for 3% of all osteosarcomas. It has a variable clinical presentation, ranging from asymptomatic to multiple pathological fractures, mainly involving long bones, and less frequently the axial skeleton and soft tissues.

Case presentation

We present the case of a 25-year-old Hispanic woman, previously healthy, with a 1-month history of dyspnea on exertion, intermittent dry cough, hyporexia, and intermittent unquantified fever. She presented to the emergency department with a sudden increase in dyspnea during which she quickly entered ventilatory failure and cardiorespiratory arrest with pulseless electrical activity. Resuscitation maneuvers and orotracheal intubation were initiated, but effective ventilation was not achieved despite intubation and she was transferred to the intensive care unit of our institution. The chest radiograph showed a mediastinal mass that occluded and displaced the airway. The chest tomography showed a large mediastinal mass that involved the pleura and vertebral bodies. A thoracoscopic biopsy was performed that documented a conventional giant cell-rich osteosarcoma. The patient was considered to be inoperable due to the size and extent of the tumor and subsequently died.

Conclusions

The giant cell-rich osteosarcoma is a very rare histological variant of conventional osteosarcoma. Few cases of this type of osteosarcoma originating from the spine have been reported in the literature, and to our knowledge none of the reported cases included invasion to the chest cavity with airway compression and fatal acute respiratory failure that was present our case. Radiological and histological features of the GCRO must be taken into account to make a prompt diagnosis.

Brown tumor complicating end-stage kidney disease

Longstanding, severe hyperparathyroidism (HPT) can lead to the formation of "brown tumors". A brown tumor is a radiolucent bone lesion that is locally destructive; it is not a neoplasm, but rather a stromal mass consisting of fibrous tissue, poorly mineralized woven bone, and supporting vasculature. These tumors are a rare complication of advanced primary or secondary HPT. We present a young female with chronic kidney disease (CKD) on hemodialysis with uncontrolled secondary HPT (SHPT). The patient presented with progressive lower extremity weakness and back pain. CT imaging showed multiple lytic bone lesions involving several ribs and the spine. Subsequent MRI imaging of the thoracic and lumbar spine confirmed expansile bone lesions consistent with brown tumors. One mass protruded into the spinal canal causing severe stenosis at T3 with underlying cord edema. The other lesion at T12 caused only moderate spinal canal stenosis. Our patient underwent urgent neurosurgical resection of the tumor at T3 followed by subtotal parathyroidectomy (PTX).

Mechanisms of Cytotoxicity of Chemical Agents to Giant Cell Tumors: An In Vitro Study

Background

Various chemical agents have been used as an adjuvant treatment for giant cell tumor (GCT). However, the comparative effect of these chemicals remains unclear.

Methods

Multinucleated and spindle cells from cultured GCT patients, characterized by Nanog and Oct4 expression with RT-PCR, were directly administered, in vitro, with concentrations of 1%, 3%, and 5% of H₂O₂ and 75%, 85%, and 95% of ethanol for 10 minutes and concentrations of 0.003%, 0.005%, 0.01%, 0.03%, 0.1%, and 0.3% of H₂O₂ for 5 minutes and were incubated for 24 hours. Cell morphology, cell viability, and flow cytometry after various concentrations of H₂O₂ and ethanol exposure were assessed.

Results

H₂O₂ in all concentrations caused loss of cell viability. The number of viable cells after H₂O₂ exposure was related to the concentration-dependent effect. The initial viable spindle-shaped cell, multinucleated giant cell, and round-epithelioid cell had morphological changes into fragmented nonviable cells after exposure to H₂O₂. Flow cytometry using Annexin V showed cell death due to necrosis, with the highest concentration amounting to 0.3%.

Conclusion

Administering local chemical adjuvants of H₂O₂ in vitro caused loss of viable GCT cells. The number of viable cells after H₂O₂ exposure was related to the concentration-dependent effect, whereas reducing concentration of H₂O₂ may cause loss of viability and morphology of cultured GCT cells with the apoptotic mechanism.

Immunohistochemical expression of stem cell markers OCT-4 and SOX-2 in giant cell tumor, central giant cell granuloma, and peripheral giant cell granuloma

OBJECTIVES

This study aimed to evaluate and compare the immunohistochemical expression of OCT-4 and SOX-2 and to determine their use in differentiating giant cell tumor (GCT) from central giant cell granuloma (CGCG) and peripheral giant cell granuloma (PGCG).

STUDY DESIGN

Formalin-fixed, paraffin-embedded tissue blocks of 10 histopathologically diagnosed cases of GCT, CGCG, or PGCG were examined for anti-OCT-4 and anti-SOX-2 antibodies. Nuclear staining of stromal mononuclear cells and multinucleated giant cells was considered positive for OCT-4 and SOX-2 expression.

RESULTS

Nuclear immunoexpression of OCT-4 in stromal mononuclear cells was observed in 80% (8 of 10) of GCT cases, whereas none of the CGCG and PGCG cases showed OCT-4 immunoreactivity. SOX-2 immunoreactivity was negative in GCT, CGCG, and PGCG.

CONCLUSIONS

OCT-4 immunopositivity in GCT can be used as a cancer stem cell marker to differentiate GCT from CGCG and PGCG. The presence of OCT-4 in GCT versus its complete absence in CGCG and PGCG suggests that these three conditions are separate entities. The absence of stem cell marker OCT-4 and SOX-2 raises questions regarding their role in the pathogenesis of CGCG and PGCG.

Role of cancer stem cells in the development of giant cell tumor of bone

The primary bone tumor is usually observed in adolescence age group which has been shown to be part of nearly 20% of the sarcomas known today. Giant cell tumor of bone (GCTB) can be benign as well as malignant tumor which exhibits localized dynamism and is usually associated with the end point of a long bone. Giant cell tumor (GCT) involves mononuclear stromal cells which proliferate at a high rate, multinucleated giant cells and stromal cells are equally present in this type of tumor. Cancer stem cells (CSCs) have been confirmed to play a potential role in the development of GCT. Cancer stem cell-based microRNAs have been shown to contribute to a greater extent in giant cell tumor of bone. CSCs and microRNAs present in the tumors specifically are a great concern today which need in-depth knowledge as well as advanced techniques to treat the bone cancer effectively. In this review, we attempted to summarize the role played by cancer stem cells involving certain important molecules/factors such as; Mesenchymal Stem Cells (MSCs), miRNAs and signaling mechanism such as; mTOR/PI3K-AKT, towards the formation of giant cell tumor of bone, in order to get an insight regarding various effective strategies and research advancements to obtain adequate knowledge related to CSCs which may help to focus on highly effective treatment procedures for bone tumors.

Outcomes of En bloc resection followed by reconstruction of giant cell tumor around knee and distal radius. A case series

INTRODUCTION

This study is to evaluate the outcomes of En bloc resection and reconstruction in patients with GCT of the bone around the knee and in the distal radius.

MATERIALS AND METHODS

We reviewed 41 cases of GCT of the bone that was treated by En bloc resection around the knee joint and in the distal radius from 2011 to 2018. The local recurrence, metastases, complications and functional score were evaluated for each operation technique.

RESULTS

The average of MSTS score for all group was 78% (excellent). In the knee joint, the megaprostheses group had an excellent MSTS score of78.9% and good 21.1%. The MAMC group had an excellent MSTS score of40.0%, good 50.0% and fair 10.0%. One patient in the megaprostheses group had metastasis to the lung and 1 patient in the knee arthrodesis group has a recurrence. Infection occurred in 2 cases of megaprostheses while only 1 case in MAMC. Both of the groups in knee joint GCT had 1 patient with implant loosening. In the distal radius, FVFG group had an excellent MSTS score 100% and NVFG group had an excellent score 77.7%, good 11.1% and fair 11.1%. One patient in the NVFG group had an infection, 1 patient has implant loosening and another one patient had graft failure. Two patients in the NVFG group had a recurrence. No metastasis was found in both of the group types of surgery in distal radius GCT.

CONCLUSION

Functional outcome of a patient with GCT of the bone after En bloc resection and reconstruction with the above techniques had comparable results with previous studies.

A Comparative Analysis of p63 Expression in Giant Cell Tumour (GCT), Central Giant Cell Granuloma (CGCG) and Peripheral Giant Cell Granuloma (PGCG)

Giant cell tumour (GCT) is locally aggressive benign neoplasm of long bones whereas giant cell granulomas; central giant cell granuloma (CGCG) and peripheral giant cell granuloma (PGCG); are tumour-like conditions of the oral cavity. This study aimed to evaluate and compare the immunohistochemical expression of p63 in GCT, CGCG, PGCG and determine whether p63 can be used as a diagnostic, prognostic and differential biomarker between these entities. Histopathologically diagnosed 10 cases of GCT, 20 cases of CGCG and 20 cases of PGCG were subjected to p63 immunohistochemical staining. The percentage of p63-positive cells was semi-quantitatively assessed on the whole section. Intergroup comparison was done using Kruskal-Wallis test and one-way ANOVA. The value p < 0.05 was considered to be statistically significant and value p < 0.01 was considered to be statistically highly significant. p63 immunoexpression was seen in 100% (10/10) cases of GCT whereas CGCG and PGCG revealed the complete absence of p63 immunopositivity. These results showed a highly significant difference in p63 expression between GCT, CGCG and PGCG (p < 0.01). No difference was noted between CGCG and PGCG. GCT is a distinct entity when compared with CGCG and PGCG. Even aggressive CGCG also did not show p63 immunopositivity, so it is not a prognostic marker. Also, p63 cannot differentiate between CGCG and PGCG.

Bisphosphonate-loaded Bone Cement as a Local Adjuvant Therapy for Giant Cell Tumor of Bone: A 1 to 12-Year Follow-up Study

BACKGROUND

Historically, nontargeted adjuvant therapies such as liquid nitrogen, phenol, argon beam, and alcohol have been applied locally after curettage of giant cell tumors (GCT) in the extremities. Systemic bisphosphonates (BP) and denosumab have emerged as osteoclast-targeting therapies because osteoclast-like giant cells, responsible for aggressive bone resorption, are susceptible to BP or denosumab. However, such drugs may cause systemic side effects. We examined the effects of an alternative intraoperative local delivery of BP on GCTs.

MATERIALS AND METHODS

In total, 17 patients with GCTs underwent extended surgical curettage procedures consisting of high-speed burring, traditional adjuvant therapy, and application of BP-loaded polymethylmethacrylate bone cement. Clinical data and follow-up radiographs were reviewed to investigate local recurrence (LR) rate and complications in a retrospective manner.

RESULTS

There were 6 males and 11 females (mean age, 33.7 y). There were no cases of pulmonary metastases. Patient follow-up ranged from 1 to 12 years. There was 1 LR during the follow-up period for an LR rate of 5.9%. The mean final Musculoskeletal Tumor Society (MSTS) score was 29. There were no systemic or localized avascular necrosis or atypical fractures related to BPs noted.

CONCLUSIONS

BP-loaded polymethylmethacrylate is a targeted local adjuvant therapy that is feasible, safe, and may reduce LRs while alleviating the risk of systemic side effects of BPs such as avascular necrosis of jaw and atypical femur fractures. Future prospective randomized clinical trials will strengthen the level of evidence of this proposed targeted therapy.

LEVEL OF EVIDENCE

Therapeutic level IV-see instructions for authors for a complete description of evidence.

Histopathology of giant cell tumors of the bone: With special emphasis on fibrohistiocytic and aneurysmal bone cyst like components

Objective

The aim of this study was to define histopathological features of giant cell tumor of bone, especially accompanying fibrohistiocytic or aneurysmal bone cyst like components, in the light of our institutions experience.

Methods

A total of 120 cases (64 females and 56 males; mean age: 36.2 (12–80)) with ‘GCT’ diagnosed between the years 1996–2016 were included in this retrospective analysis. Cases were evaluated according to clinical features such as age, gender, localization, recurrence, metastasis and histopathological features.

Results

Tumors were localized most frequently at proximal tibia and distal femur, respectively. In 11 cases areas rich in fibrohistiocytic component and in 20 cases aneurysmal bone cyst like component were observed. In 2 cases both components were present. Twenty three cases recurred. In 1 case which was primarily located at calcaneus, tumor metastasized to lung 4 years later during follow-up.

Conclusion

GCT can be confused with other tumor or tumor-like lesions involving giant cells. Secondary changes such as fibrohistiocytic or aneurysmal bone cyst-like components and coagulation necrosis were frequently seen in conventional giant cell tumor of bone. For tumors having prominent fibrohistiocytic and/or aneurysmal bone cyst-like components, in order to detect characteristic areas representing GCT, additional sampling is essential. Although secondary histopathological changes do not appear to affect clinical outcome, these features are important in differential diagnosis. Approximately one fifth of GCT cases show recurrence and sacrum and foot bones were the most frequent sites for recurrence.

Level of evidence

Level IV, diagnostic study.

Prognosis of metastatic giant cell tumor of bone in the pre-denosumab era. A systematic review and a meta-analysis

Background

Data on long-term prognosis of metastatic GCT (mGCT) is scant. The frequency of spontaneous regressions (SRs) is unknown. We aimed to estimate the prognosis of mGCT.

Methods

We searched electronic scientific literature databases and generic Internet from January 1980 to August 2017. After identifying eligible studies we performed descriptive analyses and meta-analyses to estimate overall survival (OS), disease specific survival (DSS) and frequency of SRs in the years before the widespread use of denosumab. We performed pre-specified subgroup analyses of studies published before and after 2000 and of those with more and less than 10 years of follow-up.

Results

After retrieving and combining data from 26 relevant retrospective case-series totaling 242 patients with a median follow-up of 6.9 years, the estimated pooled OS was 86.9% (95% CI 78.0-94.2). Pooled DSS was 88.0% (95% CI 79.7-94.7). SRs were observed in 4.5% of patients. In the subgroup of studies published after 2000 mGCT was the only cause of death of affected subjects. In case-series with a follow-up longer than 10 years pooled DSS was 69.7% (95% CI 25.5-99.8).

Conclusions

To our knowledge this is the first study to derive estimated pooled OS and DSS of mGCT based on a large dataset. SRs were not exceptional phenomena. In a long run the disease could impact in a significant way on the life expectancy of affected subjects.

Identification of new genes associated to senescent and tumorigenic phenotypes in mesenchymal stem cells

Although human mesenchymal stem cells (hMSCs) are a powerful tool for cell therapy, prolonged culture times result in replicative senescence or acquisition of tumorigenic features. To identify a molecular signature for senescence, we compared the transcriptome of senescent and young hMSCs with normal karyotype (hMSCs/n) and with a constitutional inversion of chromosome 3 (hMSC/inv). Senescent and young cells from both lineages showed differentially expressed genes (DEGs), with higher levels in senescent hMSCs/inv. Among the 30 DEGs in senescent hMSC/inv, 11 are new candidates for biomarkers of cellular senescence. The functional categories most represented in senescent hMSCs were related to cellular development, cell growth/proliferation, cell death, cell signaling/interaction, and cell movement. Mapping of DEGs onto biological networks revealed matrix metalloproteinase-1, thrombospondin 1, and epidermal growth factor acting as topological bottlenecks. In the comparison between senescent hMSCs/n and senescent hMSCs/inv, other functional annotations such as segregation of chromosomes, mitotic spindle formation, and mitosis and proliferation of tumor lines were most represented. We found that many genes categorized into functional annotations related to tumors in both comparisons, with relation to tumors being highest in senescent hMSCs/inv. The data presented here improves our understanding of the molecular mechanisms underlying the onset of cellular senescence as well as tumorigenesis.

The distinct clinical features of giant cell tumor of bone in pagetic and non-pagetic patients are associated with genetic, biochemical and histological differences

Giant Cell Tumor of Bone (GCT) is a tumor characterized by neoplastic mesenchymal stromal cells and a high number of osteoclast-like multinucleated giant cells. Rarely, GCT could arise in bones affected by Paget's disease of bone (GCT/PDB). Although it is already known that GCT/PDB and GCT show a different clinical profile regarding the age-onset and skeletal localization, our deep clinical comparison between the two GCT/PDB and GCT cohorts, permitted us to identify additional differences (e.g. focality, ALP serum levels, the 5-year survival rate and the familial recurrence), strongly suggesting a different molecular basis. Accordingly, driver somatic mutations in H3F3A and IDH2 were described in GCT patients, while we recently identified a germline mutation in ZNF687 as the genetic defect of GCT/PDB patients. Here, we detected H3F3A mutations in our GCT cohort, confirming its molecular screening as the elected diagnostic tool, and then we excluded the two-hit in H3F3A and IDH2 as the trigger event for the GCT/PDB development. Importantly, we also identified an alternative biochemical profile with GCT/PDB not exhibiting the up-regulation of the GCT marker FGFR2IIIc. Finally, our histological analysis also showed a different appearance of the two forms of the tumor, with GCT/PDB showing a higher number of osteoclast-like giant cells (twice), with an abnormal number of nuclei per cell, corroborating its different behaviour in terms of neoplastic properties. We demonstrated that the distinct clinical features of pagetic and conventional GCT are associated with different genetic background, resulting in a specific biochemical and histological behaviour of the tumour.

Risks and benefits of combining denosumab and surgery in giant cell tumor of bone-a case series

Background

The RANK ligand inhibitor denosumab is being investigated for treatment of giant cell tumor of bone, but the available data in the literature remains sparse and controversial. This study analyzes the results of combining denosumab with surgical treatment and highlights possible changes for the oncologic surgeon in daily practice.

Methods

A total of 91 patients were treated surgically for giant cell tumor of bone between 2010 and 2014 in an institution, whereas 25 patients of the total additionally received denosumab and were part of this study. The average age of the patients was 35 years. Eleven patients received denosumab pre- and postoperatively, whereas with 14 patients, the denosumab treatment was applied either before (7 patients) or after (7 patients) the surgery. The average preoperative therapy duration was 3.9 months and the postoperative therapy 6 months by default.

Results

Sixteen patients presented a large tumor extension necessitating a resection of the involved bone or joint. In 10 of these patients, the indication for a resection procedure was abandoned due to the preoperative denosumab treatment and a curettage was performed. In the remaining six cases, the surgical indication was not changed despite the denosumab treatment, and two of them needed a joint replacement after the tumor resection. Also with patients treated with curettage, denosumab seems to facilitate the procedure as a new peripheral bone rim around the tumor was built, though a histologic analysis reveals viable tumor cells persisting in the denosumab-induced bone formation.

After an average follow-up of 23 months, one histologically proven local recurrence occurred, necessitating a second curettage. A second patient showed a lesion in the postoperative imaging highly suspicious for local relapse which remained stable under further denosumab treatment. No adverse effect of the denosumab medication was observed in this study.

Conclusions

Denosumab can be a help to the oncologic surgeon by reconstituting a peripheral rim and switching the stage from aggressive to active or latent disease. But as tumor cells remain in the new-formed bone, the surgical technique of curettage has to be changed from gentle to more aggressive to avoid higher local recurrence rates.

Population-based study of giant cell tumor of bone in Sweden (1983-2011)

INTRODUCTION

Giant-cell tumor of bone (GCTB) is a locally aggressive histologically benign neoplasm with a less common malignant counterpart. Longitudinal data sources on GCTB are sparse, limited to single institution case series or surgical outcomes studies. The Swedish Cancer Registry is one of the few national population-based databases recording GCTB, representing a unique source to study GCTB epidemiology. We estimated incidence rate (IR) and overall mortality rates based on registry data.

MATERIALS AND METHODS

We identified patients with a GCTB diagnosis in the Swedish Cancer Registry from 1983 to 2011: benign (ICD-7 196.0-196.9; PAD 741) and malignant (PAD 746). Results were stratified by age at diagnosis, gender, and anatomical lesion location.

RESULTS

The cohort included 337 GCTB cases (IR of 1.3 per million persons per year). The majority (n=310) had primary benign GCTB (IR of 1.2 per million per year). Median age at diagnosis was 34 years (range 10-88) with 54% (n=183) females. Malignant to benign ratio for women was 0.095 (16/167) and for men 0.077 (11/143). Incidence was highest in the 20-39 years age group (IR of 2.1 per million per year). The most common lesion sites were distal femur and proximal tibia. Mortality at 20 years from diagnosis was 14% (n=48) and was slightly higher for axial (17%; n=6) and pelvic (17%; n=4) lesions. Recurrence occurred in 39% of primary benign cases and 75% of primary malignant cases.

CONCLUSIONS

In our modern population-based series primary malignant cases were uncommon (8%), peak incidence 20-39 years with slight predominance in women. Recurrence rates remain significant with overall 39% occurring in benign GCTB, and 75% in malignant form. The linkage between databases allowed the first population based estimates of the proportion of patients who received surgery at initial GCTB diagnosis, and those who also received subsequent surgeries.

Galectin-3 Cleavage Alters Bone Remodeling: Different Outcomes in Breast and Prostate Cancer Skeletal Metastasis

Management of bone metastasis remains clinically challenging and requires the identification of new molecular target(s) that can be therapeutically exploited to improve patient outcome. Galectin-3 (Gal-3) has been implicated as a secreted factor that alters the bone microenvironment. Proteolytic cleavage of Gal-3 may also contribute to malignant cellular behaviors, but has not been addressed in cancer metastasis. Here, we report that Gal-3 modulates the osteolytic bone tumor microenvironment in the presence of RANKL. Gal-3 was localized on the osteoclast cell surface, and its suppression by RNAi or a specific antagonist markedly inhibited osteoclast differentiation markers, including tartrate-resistant acid phosphatase, and reduced the number of mature osteoclasts. Structurally, the 158-175 amino acid sequence in the carbohydrate recognition domain (CRD) of Gal-3 was responsible for augmented osteoclastogenesis. During osteoclast maturation, Gal-3 interacted and colocalized with myosin-2A along the surface of cell-cell fusion. Pathologically, bone metastatic cancers expressed and released an intact form of Gal-3, mainly detected in breast cancer bone metastases, as well as a cleaved form, more abundant in prostate cancer bone metastases. Secreted intact Gal-3 interacted with myosin-2A, leading to osteoclastogenesis, whereas a shift to cleaved Gal-3 attenuated the enhancement in osteoclast differentiation. Thus, our studies demonstrate that Gal-3 shapes the bone tumor microenvironment through distinct roles contingent on its cleavage status, and highlight Gal-3 targeting through the CRD as a potential therapeutic strategy for mitigating osteolytic bone remodeling in the metastatic niche.

Bortezomib Inhibits Giant Cell Tumor of Bone through Induction of Cell Apoptosis and Inhibition of Osteoclast Recruitment, Giant Cell Formation, and Bone Resorption

Giant cell tumor of bone (GCTB) is a rare and highly osteolytic bone tumor that usually leads to an extensive bone lesion. The purpose of this study was to discover novel therapeutic targets and identify potential agents for treating GCTB. After screening the serum cytokine profiles in 52 GCTB patients and 10 normal individuals using the ELISA assay, we found that NF-κB signaling-related cytokines, including TNFα, MCP-1, IL1α, and IL17A, were significantly increased in GCTB patients. The results were confirmed by IHC that the expression and activity of p65 were significantly increased in GCTB patients. Moreover, all of the NF-κB inhibitors tested suppressed GCTB cell growth, and bortezomib (Velcade), a well-known proteasome inhibitor, was the most potent inhibitor in blocking GCTB cells growth. Our results showed that bortezomib not only induced GCTB neoplastic stromal cell (NSC) apoptosis, but also suppressed GCTB NSC-induced giant cell differentiation, formation, and resorption. Moreover, bortezomib specifically suppressed GCTB NSC-induced preosteoclast recruitment. Furthermore, bortezomib ameliorated GCTB cell-induced bone destruction in vivo As a result, bortezomib suppressed NF-κB-regulated gene expression in GCTB NSC apoptosis, monocyte migration, angiogenesis, and osteoclastogenesis. Particularly, the inhibitory effects of bortezomib were much better than zoledronic acid, a drug currently used in treating GCTB, in our in vitro experimental paradigms. Together, our results demonstrated that NF-κB signaling pathway is highly activated in GCTB, and bortezomib could suppress GCTB and osteolysis in vivo and in vitro, indicating that bortezomib is a potential agent in the treatment of GCTB. Mol Cancer Ther; 15(5); 854-65. ©2016 AACR.

Expressions and clinical significance of factors related to giant cell tumor of bone

BACKGROUND

Giant cell tumor of bone (GCTB) is a relatively rare tumor of bone, characterized by numerous multinucleated cells, severe osteolysis, and local recurrence.

PURPOSE

To explore the role of S-phase kinase-interacting protein 2 (Skp2), cyclin-dependent kinase inhibitor p27, and the transcription factor E2F-1 expression in the development of GCTB, and the relationship of expression of these proteins with tumor recurrence.

METHODS

Forty-four patients with GCTB were selected and demographic and clinical data were collected. The levels of Skp2, p27, and E2F-1 protein expression were immunohistochemically assessed in surgical specimens.

RESULTS

Skp2, p27, and E2F-1 proteins were detected in the nuclei of mononuclear stromal cells. Positive Skp2 expression was observed in 66% (29/44) of GCTB patient samples, and positive p27 expression was found in 39% (17/44) of samples. Within almost all GCTB patients, there was an inverse correlation between Skp2- and p27-positive tumor cells. Positive expression of E2F-1 was present in 28 of 44 (64%) patients. In addition, expression of skp2 and p27, infiltration of soft tissues, and surgical operation were significantly associated with recurrence in patients with GCTB.

CONCLUSION

The immunohistochemical assessment of Skp2, p27 and E2F-1 may be useful in the diagnosis of GCTB and prediction of its prognosis.

Prognostic role of nuclear factor/IB and bone remodeling proteins in metastatic giant cell tumor of bone: A retrospective study

Giant cell tumor of bone (GCTb) represents 5% of bone tumors, and although considered benign, 5% metastasize to the lung. The expression of proteins directly or indirectly associated with osteolysis and tumor growth was studied on 163 samples of GCTb. Of these, 33 patients developed lung metastasis during follow-up. The impact of tumor-host interaction on clinical aspects was evaluated with the aim of finding specific markers for new biological therapies, thus improving clinical management of GCTb. Protein expression was evaluated by immunohistochemical analysis on Tissue Microarray. The majority of GCTb samples from patients with metastatic disease were strongly positive to RANKL and its receptor RANK as well as to CAII and MMP-2 and to pro-survival proteins NFIB and c-Fos. Kaplan-Meier analysis indicated a significant difference in metastasis free survival curves based on protein staining. Interestingly, the statistical correlation established a strong association between all variables studied with a higher τ coefficient for RANK/RANKL, RANK/NFIB, and RANKL/NFIB pairs. At multivariate analysis co-overexpression of NFIB, RANK and RANKL significantly increased the risk of metastasis with an odds ratio of 13.59 (95%CI 4.12-44.82; p < 0.0005). In conclusion, the interconnection between matrix remodeling and tumor cell activity may identify tumor-host endpoints for new biological treatments.

'Salvage Treatment' of Aggressive Giant Cell Tumor of Bones with Denosumab

Giant cell tumor of the bone (GCTB) presents as a lytic lesion of epiphyseometaphyseal regions of the long bones usually during the second to the fourth decade with female predilection. Histologically, they are formed of neoplastic mononuclear cells with a higher receptor activator of nuclear factor kappa-B ligand (RANKL) expression responsible for the aggressive osteolytic nature of the tumour. RANKL helps in the formation and functioning of osteoclasts. A newer molecule, Denosumab, is a monoclonal antibody directed against RANKL and thus prevents the formation and function of osteoclasts. Management of refractory, multicentric, recurrent, or metastatic GCTB remains challenging as achieving a tumor-free margin surgically is not always possible. Denosumab may play a crucial role, especially in the management of such difficult lesions. We present three cases of locally aggressive GCTB (involving proximal humerus, sacrum, and proximal femur) that were treated and responded very well to Denosumab therapy.

RANK pathway in giant cell tumor of bone: pathogenesis and therapeutic aspects

Giant cell tumor is a relatively uncommon but painful tumor of bone, which can metastasize to the lungs. The RANK pathway is often reported to be involved in the pathogenesis of giant cell tumor of bone (GCTB). This pathway is a key signaling pathway of bone remodeling that plays a critical role in differentiation of precursors into multinucleated osteoclasts, and activation of osteoclasts leading to bone resorption. Dysregulation of RANK ligand (RANKL)-RANK-osteoprotegerin (OPG) signaling cascade induces the imbalance between bone formation and bone resorption, which leads to the changes in bone mass, increases osteoclast-mediated bone destruction, bone metastasis, and the progression of existing skeletal tumors. Recent evidences have shown that targeting the components of RANKL-RANK-OPG signaling pathway is a promising approach in the treatment of GCTB. This review study has focused on the association of RANKL-RANK-OPG pathway in the pathogenesis and progression of GCTB as well as discussed the possible therapeutic strategies by targeting this pathway.

Giant cell tumour of bone: new treatments in development

Giant cell tumour of bone (GCTB) is a benign osteolytic tumour with three main cellular components: multinucleated osteoclast-like giant cells, mononuclear spindle-like stromal cells (the main neoplastic components) and mononuclear cells of the monocyte/macrophage lineage. The giant cells overexpress a key mediator in osteoclastogenesis: the RANK receptor, which is stimulated in turn by the cytokine RANKL, which is secreted by the stromal cells. The RANK/RANKL interaction is predominantly responsible for the extensive bone resorption by the tumour. Historically, standard treatment was substantial surgical resection, with or without adjuvant therapy, with recurrence rates of 20–56 %. Studies with denosumab, a monoclonal antibody that specifically binds to RANKL, resulted in dramatic treatment responses, which led to its approval by the United States Food and Drugs Administration (US FDA). Recent advances in the understanding of GCTB pathogenesis are essential to develop new treatments for this locally destructive primary bone tumour.

Local administration of zoledronic acid for giant cell tumor of bone

Giant cell tumor of bone is a locally aggressive tumor with a high local recurrence rate. Several adjuvant therapies have been employed to reduce the recurrence rate, but their effectiveness remains controversial. The authors attempted local administration of zoledronic acid, a nitrogen-containing bisphosphonate that strongly inhibits bone resorption, as an adjuvant treatment for histologically proven giant cell tumor of bone in 5 patients at their institution. After biopsy, 4 patients were treated with local administration of zoledronic acid with artificial bone and 1 was treated with zoledronic acid without artificial bone. Histologic response to the treatment was evaluated with surgically resected specimens. The 4 patients treated with artificial bone showed local control, with histologic tumor necrosis rates of 90%, 90%, 50%, and 10%. Magnetic resonance imaging showed poor gadolinium enhancement, and histologic examination after local zoledronic acid treatment showed tumor necrosis. One patient without artificial bone showed no histologic tumor necrosis and had local recurrence in soft tissue 18 months after tumor resection. A 3-week waiting period between biopsy and zoledronic acid treatment appears reasonable from the histological study. Complication of this therapy was delayed wound healing and it occurred in 2 cases. Taken together, this case series suggests that local administration of zoledronic acid with artificial bone is a potential adjuvant therapy for giant cell tumor of bone. On the other hand, effective local administration of zoledronic acid requires some bone matrix, including artificial bone. Campanacci's grading is important for predicting the effect of local administration of zoledronic acid.

Early evaluation of the therapeutic effect of denosumab on tartrate-resistant acid phosphatase 5b expression in a giant cell tumor of bone: a case report

Background

Giant cell tumor of bone is an osteolytic, usually benign, tumor characterized by the infiltration of osteoclast-like giant cells. The receptor activator of nuclear factor kappa-B ligand pathway has been shown to play a key role in the pathogenesis of giant cell tumor. Treatment for refractory, recurrent, or metastatic giant cell tumor remains challenging. A monoclonal antibody to receptor activator of nuclear factor kappa-B ligand, denosumab, offers promise in these patients. Tartrate-resistant acid phosphatase 5b, a bone resorption marker, is secreted from osteoclasts and this marker is reported to be high in patients with giant cell tumor of bone. We investigated the effects of denosumab and the usefulness of a tartrate-resistant acid phosphatase 5b as a monitoring marker in the management of a refractory giant cell tumor of bone.

Case presentation

A 41-year-old Japanese male with right ischiac pain was diagnosed with a giant cell tumor in his right ischium. Since the tumor extended to the acetabulum, there was a possibility that en bloc resection might significantly impair function of the hip joint and curettage could cause massive bleeding. Therefore, denosumab therapy (120 mg, administered 3 times every 4 weeks) was performed before radical surgery. The giant cell tumor of bone was treated with denosumab successfully. No adverse reaction was noted. Tartrate-resistant acid phosphatase 5b secretion was measured in the patient’s serum to monitor the response to denosumab, and a rapid normalization of the marker was observed after the first denosumab administration.

Conclusion

This case suggests that denosumab therapy might be an option for treating refractory giant cell tumor of bone, and that tartrate-resistant acid phosphatase 5b might be an early marker with which to monitor the efficacy of denosumab therapy for refractory giant cell tumor.

Pulmonary metastasis of giant cell tumor of bones

Giant cell tumor of bone (GCTB) accounts for 5% of primary skeletal tumors. Although it is considered to be a benign lesion, there are still incidences of pulmonary metastasis. Pulmonary metastasis of GCTB may be affected by tumor grading and localization as well as the age, gender and overall health status of the patient. Patients with local recurrence are more likely to develop pulmonary metastasis of GCTB. High expression of some genes, cytokines and chemokines may also be closely related to the metastatic potential and prognosis of GCTB. The treatment of the primary GCTB is key to the final outcome of the disease, as intralesional curettage has a significantly higher local recurrence and pulmonary metastasis rate than wide resection. However, even patients with pulmonary metastasis seem to have a good prognosis after timely and appropriate surgical resection. It is hoped that with the development of novel surgical methods and drugs, pulmonary metastasis of GCTB can be prevented and treated more effectively.

The multidisciplinary management of giant cell tumor of bone

Giant cell tumor of bone is a locally aggressive lesion with a predilection for local recurrence, and in a small proportion of patients, metastatic disease can develop. Surgery is the mainstay of management for extremity-based lesions. For tumors located in challenging anatomical locations such as the sacrum and spine however, surgery may be associated with unacceptable functional morbidity. There are limited data regarding other treatment modalities such as radiation therapy, cytotoxic chemotherapy, interferon and bisphosphonates. Serial arterial embolization can be effective in some cases. Recent evidence has demonstrated denosumab to be a promising agent in the treatment of unresectable or metastatic disease.