Giant Cell Tumor of Bone

The patient remained well, without local recurrence or metastasis during 6 years of follow-up. The present tumor highlights the rarity of the location, and the diagnostic challenges encountered prior to surgery.

Systemic agents such as denosumab or bisphosphonates remain investigational, and radiotherapy is generally contraindicated due to malignant transformation risk...Awareness of risk factors, early imaging-based detection, and complete surgical excision are critical for optimal outcomes. Further multicenter studies are required to define surveillance protocols, validate molecular predictors, and clarify the role of systemic therapy in this challenging condition.

The results suggest the potential participation of PD-1, PD-L1, and PD-L2 in the pathogenesis of CGCG, PGCG, and GCTB. The locally aggressive behavior of GCTB could be associated with a higher osteoclastogenic and immunosuppressive microenvironment in these neoplasms.

P=N/A, N=800, Recruiting, University of Calgary

Serum calcium and parathyroid hormone measurements are essential in the evaluation of bone lesions. Hypercalcemia may indicate primary hyperparathyroidism but can also occur in myeloma, metastases, or granulomatous diseases.Brown tumours (BTs) and giant cell tumours (GCTs) of bone may overlap; BTs are associated with hypercalcemia and H3F3A negativity, while GCTs are characterized by normal calcium levels and H3F3A positivity.A multidisciplinary approach combining clinical, biochemical, and pathological data improves diagnostic accuracy in bone lesions by distinguishing benign, malignant and metabolic causes, ensuring appropriate management.

Sampling revealed a HMGA2::NCOR2 fusion associated with a recently described subset of giant cell-rich bone and soft tissue tumors. This case expands the differential diagnosis for cross-physeal and epiphyseal bone tumors in pediatric patients and highlights the radiological features of keratin-positive giant cell-rich tumor (KPGCT).

Immunohistochemistry with H3.3 G34W, H3.3 G34R and G34V can be used as a surrogate for detection of corresponding H3F3A gene mutations. These antibodies should be used as first-line tests for confirming the diagnosis with sequencing being restricted only to tumors negative on immunohistochemistry.

P=N/A, N=40, Not yet recruiting, Shanghai JiaoTong university Affiliated Sixth People‘s Hospital; Shanghai Jiao Tong University Affiliated Sixth People's Hospital

P=N/A, N=40, Not yet recruiting, Shanghai Sixth People's Hospital; Shanghai Sixth People's Hospital

P=N/A, N=10, Not yet recruiting, Liaoning Cancer Hospital; Liaoning Cancer Hospital

Systemic therapies targeting CSF1 or its receptor are valuable for relapsing or inoperable cases, especially D-TGCT, but their use is still limited by heavy side effects and unresponsive tumors. Overall, our understanding of the pathophysiology of these tumors, the efficacy and limitations of current therapeutic options, and the questions that remain unanswered open new avenues for research and provide opportunities to further improve patient care.

In conclusion, TAMs significantly influence the prognosis of GCTB patients and are correlated with certain invasive tumor phenotypes. Elevated TAMs levels may be associated with reduced efficacy of denosumab treatment.