Search Results (71)

Background and Clinical Significance: Malignant transformation of giant cell tumor of bone (GCTB) is a rare but clinically significant event, most commonly associated with radiotherapy, denosumab therapy, or recurrent disease. Secondary malignant transformation occurring in the absence of recognized risk factors is exceptionally uncommon. We report a rare case of high-grade sarcomatous transformation of proximal humeral GCTB after a prolonged latency period without prior radiotherapy, denosumab exposure, or documented recurrence; Case Presentation: A 27-year-old female initially presented with right shoulder pain and was diagnosed with proximal humeral GCTB. She underwent intralesional curettage and bone grafting, with histopathological confirmation of benign GCTB. Nine years later, she developed progressive shoulder pain, functional limitation, and systemic symptoms. Imaging demonstrated an aggressive lytic lesion with cortical destruction and soft-tissue extension involving the proximal humerus. Repeat curettage and histopathological evaluation revealed high-grade spindle cell sarcoma consistent with malignant transformation of GCTB. The patient received neoadjuvant chemotherapy followed by wide resection and endoprosthetic reconstruction of the proximal humerus, with additional adjuvant chemotherapy postoperatively. At two-year follow-up, she remained disease-free with excellent functional recovery and satisfactory quality of life; Conclusions: This case highlights the potential for delayed malignant transformation of GCTB even in the absence of established predisposing factors. Clinicians should maintain long-term vigilance in patients treated for GCTB, particularly when new pain, functional decline, or aggressive radiologic features develop years after initial treatment. Early recognition and multidisciplinary management are essential to optimize oncologic and functional outcomes. Full article

Background: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by fibroblast growth factor 23 (FGF-23)-secreting tumors, typically of mesenchymal origin, leading to renal phosphate wasting and severe bone demineralization and fragility fractures. Diagnosing TIO remains a significant clinical challenge, particularly when coexisting mineral metabolism disorders, such as hypercalcemic hyperparathyroidism, are masking its clinical presentation. Case Presentation: A 74-year-old woman with fragility fractures, generalized bone pain, and nephrolithiasis was initially diagnosed with primary hyperparathyroidism due to concomitant hypercalcemia, hypophosphatemia, and elevated parathyroid hormone (PTH). Despite a successful parathyroidectomy, which normalized calcium levels, severe hypophosphatemia persisted due to renal phosphate wasting. High FGF-23 levels and subsequent functional imaging indicating a somatostatin receptor-positive lesion in the left popliteal fossa led to the diagnosis of TIO. Surgical resection immediately normalized FGF-23 levels, leading to a slower rise in phosphorus during follow-up. Histopathology revealed a tophaceous-like giant cell granulomatous reaction, recalling the earlier report by Prader. Conclusions: This case highlights that parathyroid disorders can coexist with TIO, and they may delay its diagnosis. In this circumstance, a high index of clinical suspicion is represented by the persistence of hypophosphatemia post-parathyroidectomy. Full article

Background/Objectives: Sacral giant cell tumor of bone (GCTB) is a rare, mostly benign but locally aggressive neoplasm that carries significant diagnostic and treatment challenges due to its anatomic complexity, proximity to sacral nerve roots as well as the blood vessels, and potential impact on bowel, bladder, sexual, and lumbopelvic function and stability. This narrative review aimed to synthesize current evidence on the epidemiology, clinical presentation, diagnostic evaluation, classification, management strategies, outcomes, and surveillance of sacral GCTB. Methods: A focused literature search of PubMed/MEDLINE and Google Scholar was conducted for studies published between January 2000 and January 2026, with additional manual review of reference lists. Given the rarity of the tumor and the observed heterogeneity in study designs, treatment strategies, and outcomes, the evidence was synthesized narratively. Results: Sacral GCTB mainly affects young adults with an indolent nature, often presenting late with progressive low back or buttock pain, radiculopathy, or neurological deficits. Magnetic resonance imaging is the preferred modality for determining local extent, whereas histopathologic biopsy and molecular testing remain essential for definitive diagnosis. Conventional grading systems, such as Enneking and Campanacci, have limited value in sacral disease, as anatomical extent and anticipated neurological morbidity are more relevant for treatment planning. Surgery remains the cornerstone for resectable disease, yet management plans should balance local tumor control against preservation of sacral nerve roots and mechanical stability. Denosumab, selective arterial embolization, and radiotherapy may play important roles in selected unresectable or high-morbidity cases. Local recurrence remains a major concern, and long-term surveillance is recommended because tumor relapse, treatment-related morbidity, and distant metastasis may occur late. Conclusions: Current evidence supports a multidisciplinary, individualized approach to sacral GCTB, guided by tumor extent, expected neurological morbidity, and patient-centered functional outcomes. Prospective multicenter studies are needed to refine treatment algorithms and improve risk stratification. Full article

Carbon-Fiber-Reinforced Polyetheretherketone (CFR-PEEK) instrumentation is increasingly preferred in spinal oncology for its physical properties, minimizing imaging artifacts and facilitating precise postoperative radiotherapy planning and tumor surveillance. However, a significant technical limitation exists: the current unavailability of dedicated CFR-PEEK pedicle screws for the cervical spine. The smallest available implants are designed for thoracic use (minimum diameter 4.5 mm, minimum length 25 mm), posing substantial risks of neurovascular injury when applied to smaller cervical pedicles. We present a technical note/feasibility report illustrated by a single case of robot-assisted placement of thoracic CFR-PEEK screws in the cervical spine for the treatment of a C7 Giant Cell Tumor. Following neoadjuvant therapy with Denosumab, a single-stage, two-step circumferential resection and reconstruction was performed. The anterior step was complicated by an iatrogenic injury to the highly adherent left vertebral artery (VA), which was successfully repaired. Consequently, the posterior step required maximal precision to preserve the sole remaining intact VA on the right side. Given the anatomical mismatch between the 4.5 mm thoracic screws and the narrow cervical pedicles (measuring as narrow as 3.2 mm on the critical right side), robotic navigation (ExcelsiusGPS^®) was utilized to plan and execute safe trajectories. Specifically, on the side of the intact VA, a small, controlled medial cortical violation was planned to avoid lateral vascular compromise. The procedure resulted in rigid, artifact-free stabilization with no immediate neurological sequelae. This single-case experience suggests that robotic guidance may facilitate adaptation of thoracic CFR-PEEK instrumentation to the cervical spine in selected oncologic scenarios; reproducibility, costs, and long-term outcomes remain uncertain. Full article

Giant cell tumor of bone (GCTB) is a distinctive, intermediate-grade primary bone neoplasm defined by a neoplastic mesenchymal stromal compartment and a prominent osteoclast-rich microenvironment. Although histologically benign, GCTB is clinically consequential due to its locally destructive behavior, propensity for recurrence, and rare capacity for metastasis and malignant transformation. Over the past decade, the identification of recurrent H3F3A p.G34 mutations has fundamentally reshaped the understanding of GCTB pathogenesis, establishing the stromal cell as the true neoplastic driver and positioning the tumor as a paradigmatic epigenetically driven osteolytic disease. This narrative review focus on biology, pathophysiology, and histopathology in the era of H3F3A. H3F3A-mutant stromal cells orchestrate pathological osteoclastogenesis through dysregulated RANKL signaling and chromatin reprogramming, giving rise to the characteristic cellular admixture of osteoclast-type giant cells, mononuclear histiocytic cells, and neoplastic stromal elements. The targeted inhibition of osteoclast activity with denosumab has transformed clinical management, inducing profound morphological changes and bone formation. However, its long-term impact on local control, recurrence patterns, and malignant progression remains unclear. Collectively, GCTB exemplifies a molecularly defined bone tumor in which advances in epigenetic biology and tumor–microenvironment interactions have directly influenced diagnostic practice and therapeutic strategy. Ongoing challenges include refining risk stratification, optimizing treatment sequencing, and clarifying the biological consequences of sustained osteoclast suppression. Full article

Background: Achieving adequate margins in pelvic bone tumor resection remains difficult, as conventional navigation provides no direct three-dimensional margin feedback. We proposed an innovative dangerous region generation method based on 3D image resampling and anisotropic distance transform, integrated with computer-assisted navigation, to enhance surgical margin accuracy. This study aimed to evaluate its oncological safety, functional outcomes, and perioperative efficacy in pelvic tumor surgery. Methods: The study was conducted on 19 patients (8 males, 11 females) with primary pelvic bone tumors between May 2018 and June 2024. The age range was 19 to 66 years (mean age: 62.67 years). Histological diagnoses included chondrosarcoma (n = 6), giant cell tumor (n = 4), osteosarcoma (n = 1), chordoma (n = 2), Ewing sarcoma (n = 3), spindle cell sarcoma (n = 1), chondromyxoid fibroma (n = 1), and peripheral nerve sheath tumor (n = 1). The feasibility of the dangerous region generation method for computer-assisted pelvic tumor resection surgery was assessed by general results, oncological and functional results. Results: All patients successfully underwent surgery with a mean operative time of 252 min and average intraoperative blood loss of 1358 mL. The mean hospital stay was 22 days, and all patients completed follow-up (mean, 37 months). Two patients developed postoperative wound complications, which resolved after debridement. Adequate surgical margins were achieved in all cases. The 5-year overall survival rate was 75.6%, increasing to 80.0% among patients with wide-margin resections. At the final follow-up, the mean MSTS score among 16 limb-salvage patients was 26.6, corresponding to an average functional recovery of 88.5%. Most patients exhibited a normal gait and were able to ambulate without assistive devices. Conclusions: This dangerous region generation method, when combined with computer-assisted techniques for pelvic bone tumor resection, is feasible and can achieve favorable clinical outcomes. Full article

Objective: Giant cell lesions (GCLs) share similar histopathologic features. The influence of immune involvement on the biology of giant cell lesions remains largely elusive. This study aimed to evaluate and compare lymphocyte and mast cell infiltration and distribution among three giant cell lesions. Study design: A total of 30 FFPE tissue blocks, comprising 10 PGCGs, 10 CGCGs (aggressive and nonaggressive), and 10 GCTs (aggressive and nonaggressive) of bone, were subjected to IHC staining for CD3 and CD20 lymphocyte markers and toluidine blue staining for mast cells. The mean count of positively stained cells was calculated and categorized into three scores, along with a group for negative cases. Statistical analysis was conducted to assess significance at p < 0.05. Result: Lymphocyte infiltration was observed across all lesions. CD3⁺ and CD20⁺ cell counts were significantly elevated in PGCGs, followed by CGCGs, and were lowest in GCTs of bone. In contrast, mast cell counts were high in GCTs of bone and CGCGs and low in PGCGs. Aggressive giant cell lesions of bone showed a significantly low number of CD3⁺ and CD20⁺ cells (Mann–Whitney U test; p = 0.05, 0.004) and a high number of mast cells (Mann–Whitney U test; p < 0.001) compared with nonaggressive lesions of bone. PGCGs and nonaggressive CGCGs showed comparable CD3 expression, with no significant difference between them (p = 0.59). CD20 levels were higher in nonaggressive CGCGs but did not reach statistical significance (Mann–Whitney U test; p = 0.07). Mast cell density was significantly lower in PGCGs compared with intraosseous nonaggressive CGCGs. Conclusions: The present study shows that GCTs of bone, CGCGs, and PGCGs possess distinct immune microenvironmental profiles. Aggressive lesions demonstrate reduced lymphocyte infiltration and increased mast cell density, a pattern particularly evident in GCTs of bone. This imbalance may contribute to their aggressive behavior by enabling them to escape host immune regulation. Full article

Background/Objectives: Malignant transformation of bone lesions, although rare, poses a major diagnostic and clinical challenge. Common benign lesions (e.g., osteochondroma, enchondroma, fibrous dysplasia, giant cell tumor), non-tumorous conditions (e.g., chronic osteomyelitis, irradiated bone, infarction), and low-grade malignancies (e.g., low-grade osteosarcoma, chondrosarcoma) can evolve into aggressive malignancies through distinct genetic, molecular, and microenvironmental pathways. Recognizing early malignant transformation on imaging is crucial for timely diagnosis and management. Methods: This review synthesizes current imaging characteristics, pathologic mechanisms, and clinical risk factors associated with malignant transformation of benign and low-grade malignancy bone lesions. Results: Atypical imaging findings and inaccurate biopsies can delay diagnosis. Aggressive features—such as cortical destruction, heterogeneous enhancement, and loss of internal matrix—should prompt further pathologic evaluation. Advanced imaging and a multidisciplinary approach with integrated clinicoradiologic–pathologic review are essential to minimize missed diagnoses. Patients with risk factors such as genetic syndromes, prior denosumab therapy, inadequate surgery, or prior radiation therapy require close monitoring or timely intervention. Conclusions: Radiologic–pathologic correlation remains central to distinguishing benign from malignant lesions. This review article emphasizes a comprehensive imaging-pathology overview of benign and low-grade malignancy bone lesions with malignant potential, aiming to improve diagnostic accuracy and outcomes in orthopedic oncology. Full article

Brown tumors (BTs) are rare osteolytic lesions that typically occur in association with primary or secondary hyperparathyroidism (PHP and SHP). Excessive secretion of parathyroid hormone induces increased bone resorption, resulting in lesions characterized by fibrosis, vascularization, and hemosiderin deposition. The most common sites include the jaws, ribs, pelvis, and long bones. Clinical manifestations may involve pain, swelling, or pathological fractures. We present the case of a mandibular BT in a 48-year-old female with chronic renal failure and secondary hyperparathyroidism. The patient exhibited progressive mandibular swelling with radiological features resembling an aggressive odontogenic or malignant lesion. Laboratory analysis confirmed markedly elevated parathyroid hormone levels, while scintigraphy demonstrated increased focal uptake in the mandible and ribs. Histopathological evaluation revealed multinucleated giant cells within a fibrous stroma, consistent with BT. Despite initiation of systemic endocrine therapy, the lesion continued to enlarge, necessitating complete surgical excision of the mandibular mass. This case underscores the diagnostic dilemmas of mandibular BT, which may closely mimic aggressive jaw pathologies. Importantly, while many BTs regress after systemic management of hyperparathyroidism, this case illustrates that surgical excision may be unavoidable in patients with unstable systemic status or progressive local disease. Comprehensive clinical, radiological, laboratory, and histopathological evaluation remains essential to ensure timely diagnosis and appropriate treatment. Full article

Background: Central giant cell granuloma of the jaw is a benign but potentially aggressive lesion that can cause pain, facial deformity, tooth loss, and jaw destruction. Many treatment methods are described in the literature, but the less invasive ones are associated with a higher recurrence rate. For several decades, extensive bone resection procedures have been the most effective treatment to date. This study aimed to evaluate a minimally invasive treatment protocol combining multiple weekly intralesional steroid injections with surgical removal of residual tumor tissue and chemical cauterization using Carnoy’s solution. Methods: Thirteen patients with histologically confirmed central giant cell granulomas of the jaws were treated according to the protocol, including weekly triamcinolone injections and, when necessary, fenestration of the cortical bone to access residual lesions. Patients were monitored clinically and radiologically over six years, with reconstruction of bone defects using autogenous grafts and platelet-rich fibrin. Results: The treatment effectively reduced tumor size, restored cortical bone, and allowed preservation of jaw structure. Only one recurrence was observed, and complications were minor and transient. The protocol was equally effective for both aggressive and non-aggressive lesions, regardless of patient age or comorbidities. Conclusions: These findings suggest that combining pharmacological and surgical approaches with chemical cauterization provides a safe, effective, and tissue-preserving strategy for managing central giant cell granulomas, minimizing recurrence while reducing surgical morbidity. Full article

Malignant giant cell tumor of bone (GCTB) is a rare malignant bone tumor. This analysis was conducted on patients with malignant GCTB at our center. The clinical, demographic, and prognostic characteristics were evaluated and compared. During 1 January 2015 to 31 December 2022, fifty patients were included in the study, which made up 3.3% of the contemporary GCTB patients. The clinical characteristics were comparable between the 24 patients with primary malignant GCTB (PMGCTB) and 26 patients with secondary malignant GCTB (SMGTCB). The tumor location was mainly at the axial and pelvic region (70%) and differed between the two types (p = 0.040). H3F3A pathogenic variant presented frequently in SMGCTB (p = 0.020). Cox regression analysis showed the prognostic outcomes were poor in those with a tumor located in the axial bone and sacrum with invasion of other places. H3F3A mutation status is also a risk factor, while chemotherapy and denosumab failed to demonstrate prognostic benefits. Malignant GCTB is a rare condition with a poor prognosis, especially in SMGTCB. The location and H3F3A mutation status had an influence on prognosis, and systemic therapy should be taken into consideration for patients with unfavorable prognostic features. Full article

The jaw bones can manifest various cysts and tumors of different origins and etiologies. Any bone lesions lacking any potential odontogenic origin might require more accurate diagnostics, adequate investigation, and careful patient anamnesis. In cases of sharply demarcated radiolucency or mixed radiolucent–radiopaque radiological appearance lesions, they can sometimes extend between the displaced tooth roots or cause their resorption. The scope of cortical bone in radiographic studies might have a different status, and lesions can spread outside of the bone. If no odontogenic feature is present, an additional blood examination for bone markers and calcium–phosphate markers is useful to establish any endocrine-related pathologies. In the primary hyperparathyroidism (PHP), bone blood markers and bone scintigraphy are very useful to establish the possible occurrence of brown tumor. On the other hand, in central giant cell granuloma (CGCG), only a direct tumor lesion biopsy might confirm the diagnosis, where in microscopic evaluation, mostly fibroblasts and secondary cells have multinucleated giant cells along with some accessory cells like macrophages, dendrocytes, and other endothelial cells. Because both lesions can have similar clinical and radiological appearances and unclear borders, with different shapes, sizes, and symptoms, it is quite important to compare both clinical and radiological patient characteristics. The authors aim to present how radiological studies alone can easily lead to lesion misdiagnosis. They also aim to emphasize how local treatment methods without advanced microsurgical reconstruction can, in some cases, improve patient outcomes. Full article

Background/Objectives: Brown tumors are bone manifestations of hyperparathyroidism, and they are characterized by histologic similarities with Central Giant Cell Granuloma (CGCG). Their diagnosis requires clinical, microscopic, macroscopic, and serologic correlation, as there is usually an elevation in parathormone levels due to the underlying metabolic disorder. Methods: This case describes a patient with a left mandibular lesion and a history of CGCG. Results: Through the joint analysis of clinical, histologic, and serologic findings, the diagnosis of a brown tumor associated with hyperparathyroidism was confirmed. Conclusions: This case highlights the importance of a comprehensive evaluation of oral and systemic features for accurate diagnoses and appropriate patient management. Full article

Osteosarcoma is one of the most common primary bone malignancies, typically occurring around the knee. However, the forearm is a rare site, with tumors in the proximal ulna being extremely uncommon. Primary sarcoma in this location presents a surgical challenge due to the complex anatomy and limited reconstructive options. We report a rare case of a 19-year-old female with non-metastatic, high-grade giant cell-rich osteosarcoma involving the right proximal ulna. To our knowledge, this is only the second reported adult case of this histological subtype in this location. The patient was treated at a specialized oncology center with neoadjuvant and adjuvant chemotherapy, along with wide intra-articular resection for local tumor control. Reconstruction was achieved using a novel, customized 3D-printed articulating cement spacer mold with plate osteosynthesis. Artificial elbow ligamentous reconstruction was performed using FiberTape and FiberWire sutures passed through drill holes, and the triceps tendon was reattached to the cement mold using an endobutton. This cost-effective and personalized surgical approach allowed successful joint reconstruction while maintaining elbow stability and function. Our case highlights a feasible reconstructive option for rare and anatomically challenging osteosarcoma presentations, contributing to the limited literature on proximal ulna giant cell-rich osteosarcoma. Full article

Background/Objectives: Denosumab has been considered effective for downstaging giant cell tumor of bone (GCTB), implying that it lowers the Campanacci grade rather than reducing tumor size. Preoperative tumor shrinkage holds therapeutic value by decreasing surgical complications. While previous studies have observed lesion shrinkage in some patients, no study has identified the types of patients likely to show treatment response. Thus, we sought to identify the clinical factors associated with post-denosumab GCTB size reduction. Methods: The data for 45 GCTB patients (29 females [64%], 16 males [36%], median age 32 years [range: 17–65]) who received denosumab were analyzed. Lesions were in the extremities (n = 25, 56%) or spinopelvic region (n = 20, 44%). Ten (22%) were recurrent. Lesion size reduction was assessed using two criteria: a ≥5% and a ≥5 mm decrease in the longest diameter. Univariate analyses were conducted for all variables, and those found to be significant were subjected to multivariate analyses. In addition, multicollinearity was evaluated. Subgroup analyses were performed based on lesion location and recurrence status. Results: Campanacci grade III predicted proportional shrinkage (≥5%) in all patients (OR 4.819, 95% CI 1.121–20.714) and in extremity (OR 11.171, 95% CI 1.023–122.014) and primary lesions (OR 5.781, 95% CI 1.181–28.297), and aneurysmal bone cyst (ABC)-like change was associated with absolute shrinkage (≥5 mm) in all patients (OR 8.734, 95% CI 1.159–65.845) and primary lesions (OR 11.936, 95% CI 1.074–132.69). The longest tumor diameter of ≥7 cm predicted absolute shrinkage in all patients (OR 12.380, 95% CI 1.038–147.694) and for spinopelvic lesions (OR 20, 95% CI 1.676–238.63). Conclusions: ABC-like change, Campanacci grade III, and the longest tumor diameter might predict post-denosumab GCTB shrinkage in all patients, though shrinkage varies with lesion location and recurrence status. These factors could help clinicians tailor treatment strategies in different settings. Further research is needed to explore how clinical factors pharmacologically influence denosumab-induced GCTB shrinkage. Full article