Pulmonary metastasis of giant cell tumor of the bone diagnosed by fine-needle aspiration biopsy

Increased Risk of Lung Metastases in Patients with Giant Cell Bone Tumors: A Systematic Review

Giant cell tumors of the bone are rare, usually benign, tumors consisting of large, multinucleated bone cells. Remarkably, these tumors are characterized by aggressive growth. They tend to recur frequently and, in rare cases, metastasize to the lungs. Previous studies tried to identify risk factors for lung metastasis by giant cell bone tumors. Those studies reported different results due to a small number of patients. Therefore, a particularly high risk associated with this type of bone tumor prompted this systematic review and meta-analysis to identify risk factors for the development of lung metastases. The risk factors for lung metastasis by giant cell bone tumors searched for in this study were gender, age, lung metastasis and recurrence period, follow-up time, primary or recurrent tumor, Campanacci grading, tumor localization, disease course, treatment of primary and recurrent tumors, and pulmonary metastases treated by surgery, radiation, and chemotherapy. This meta-analysis identified the features outlined above by comparing the groups of patients with giant cell bone tumors and lung metastases with the control group consisting of patients without lung metastases. The search for suitable studies revealed 63 publications with a total of 4,295 patients with giant cell bone tumors. Of these, 247 (5.8%; 95% confidence interval (95%CI) 5.1-6.5%) patients had lung metastases. Further, the risk factors for lung metastases were the following: recurrence (p < 0.0001), lung metastasis time (p < 0.0001), Campanacci grade II (p = 0.028) and grade III (p = 0.006), localization in the lower limbs (p = 0.0007), curettage (p = 0.0005), and local irradiation of the primary tumor (p = 0.008). All studies showed a high-risk bias due to the absence of blinding of the participants, personnel, and outcome assessment. Special attention should be paid to tumor recurrence in the long follow-up time, since more advanced giant cell bone tumors, particularly in lower extremities, tend to reoccur and metastasize to the lung. Surgical treatment and local irradiation should be performed thoughtfully, with extended follow-up periods.

Giant cell tumor of bone: a basic science perspective

Comprehending the pathogenesis of giant cell tumor of bone (GCT) is of critical importance for developing novel targeted treatments for this locally-aggressive primary bone tumor. GCT is characterized by the presence of large multinucleated osteoclast-like giant cells distributed amongst mononuclear spindle-like stromal cells and other monocytes. The giant cells are principally responsible for the extensive bone resorption by the tumor. However, the spindle-like stromal cells chiefly direct the pathology of the tumor by recruiting monocytes and promoting their fusion into giant cells. The stromal cells also enhance the resorptive ability of the giant cells. This review encompasses many of the attributes of GCT, including the process of giant cell formation and the mechanisms of bone resorption. The significance of the receptor activator of nuclear factor-κB ligand (RANKL) in the development of GCT and the importance of proteases, including numerous matrix metalloproteinases, are highlighted. The mesenchymal lineage of the stromal cells and the origin of the hematopoietic monocytes are also discussed. Several aspects of GCT that require further understanding, including the etiology of the tumor, the mechanisms of metastases, and the development of an appropriate animal model, are also considered. By exploring the current status of GCT research, this review accentuates the significant progress made in understanding the biology of the tumor, and discusses important areas for future investigation.

Recombinant human bone morphogenetic protein type 2 jaw reconstruction in patients affected by giant cell tumor

Giant cell tumor (GCT) is a relatively common skeletal tumor. Mandibular localization of this tumor is usually treated with resection of the tumor area. Several autogenous bone-grafting techniques are available for the restoration of large continuity defects of the mandible. However, these procedures are associated with limitations involving postoperative morbidity, difficulty in ambulation (hip graft), and pain. The development of a technique of surgical reconstruction not involving autogenous bone would offer new opportunities for facial bone reconstruction, particularly of the mandible. This study aims to underline the effect of recombinant human bone morphogenetic protein type 2 (rhBMP-2) in a collagen carrier with concomitant bone grafting material in the restoration of continuity critical-size defects after GCT resection in the mandible. The rhBMP-2 was used with absorbable collagen sponge. A total dose of 4 to 8 mg of rhBMP-2 was delivered to the surgical site in concentrations of 1.5 mg/mL. The patient was followed up over a period from 6 to 18 months. Occlusal function was initially restored with conventional prosthesis. Bone formation in the surgical area could be palpated at the end of 3 to 4 months and identified radiographically at the end of 5 to 6 months. The results clearly indicated that the use of rhBMP-2 without concomitant bone grafting materials in large critical-size mandibular defects secondary to GCT produced excellent regeneration of the area, establishing the basis for the return of prosthodontic function.

Clinical Practice: Giant Cell Tumour of the Jaw Mimicking Bone Malignancy on Three-Dimensional Computed Tomography (3D CT) Reconstruction

A wide range of diseases may present with radiographic features of osteolysis. Periapical inflammation, cysts and benign tumours, bone malignancies, all of these conditions may show bone resorption on radiograph. Features of the surrounding bone, margins of the lesion, and biological behaviour including tendency to infiltration and root resorption, may represent important criteria for distinguishing benign tumours from their malign counterpart, although the radiographic aspect of the lesion is not always predictive. Therefore a critical differential diagnosis has to be reached to choose the best management. Here, we report a case of giant cell tumour (GCT) whose radiological features by computed tomography (CT) suggested the presence of bone malignancy, whereas the evaluation of a routine OPT scan comforted us about the benign nature of the lesion. A brief review of the literature on such a benign but locally aggressive neoplasm is also provided.