Giant cell-rich osteosarcoma in long bones: clinical, radiological and pathological features.

PURPOSE: The purpose of this study was to review the clinical presentation, imaging, pathology and outcome of patients with giant cell-rich osteosarcoma (GCRO) of long bones. MATERIALS AND METHODS: Radiography (n=9), magnetic resonance imaging (MRI) (n=6), computed tomography (CT) (n=3) and clinical course of nine patients (five males and four females; mean age, 26 years) with pathologically confirmed GCRO were retrospectively reviewed. Specific imaging findings, including size, eccentricity, ossification, lysis, cystic change, expansile growth, periosteal reaction, cortical destruction, soft tissue extension and joint involvement were documented. RESULTS: Presenting symptoms were pain in six patients and pain and palpable mass in three. An ill-defined margin surrounding a predominantly osteolytic lesion was detected at the proximal tibia (n=7) or femur (n=2) on imaging studies. Seven cases showed limited ossification. Three cases had tumours in the metaphysis and six in the metaepiphysis. The average maximum tumour dimension was 4.7 cm×5.2 cm×7.8 cm. Microscopically, tumours were composed of atypical cells with scanty osteoid formation and multinucleated giant cells. All patients received chemotherapy, and surgery was performed in eight patients. Three patients were dead and six were alive at the last follow-up. CONCLUSIONS: GCRO is a rarer variant that has very close resemblance to giant cell tumour. Patients usually present nonspecific symptoms of pain and palpable mass. It usually shows an osteolytic lesion with locally spared new bone formation in the metaphysis and/or metaepiphysis on imaging. Histologically, the atypical tumour cells with osteoid formation and multinucleated giant cells are the key factor in the diagnosis and differential diagnosis.

Recurrence in giant cell tumour of bone: imaging features and risk factors.

PURPOSE: This study was done to investigate X-ray, computed tomography (CT) and magnetic resonance (MR) imaging features of recurrence in giant cell tumour of bone (GCTB) and to evaluate risk factors. MATERIALS AND METHODS: Medical records and imaging data were reviewed for 55 cases of recurrent GCTB. All images were reviewed retrospectively and independently by two radiologists experienced in skeletal musculature. The common radiological findings; factors related to tumour recurrence such as gender, age, location; pathological fracture, Campanacci grading and surgical procedure were analysed by nonparametric test (Mann-Whitney U test for two independent samples test and Kruskal-Wallis H test for multiple independent samples test). p values <0.05 were considered to indicate a statistically significant difference. RESULTS: The imaging features of recurrent GCTB were as follows: osteolytic destruction or bone resorption of graft bone or around the polymethylmethacrylate (PMMA), soft tissue mass formation and expansile change. Tumour parenchyma showed markedly heterogeneous enhancement, except for necrotic cystic cavities, on contrast-enhanced MR images. Wide resection had a smaller (p=0.031) risk of local recurrence than did intralesional curettage. There was no statistical significance in gender, age, location, pathological fracture and Campanacci staging (p>0.05). CONCLUSIONS: The risk of recurrence in GCTB was influenced by the type of surgery and adjuvants. Bone transformaresorption, soft tissue mass formation and aggravated expansile change are reliable signs of recurrence on imaging.

Primary diaphyseal osteosarcoma in long bones: imaging features and tumor characteristics.

OBJECTIVE: This study aims to assess retrospectively the imaging features of diaphyseal osteosarcoma and compare its characteristics with that of metaphyseal osteosarcoma. MATERIALS AND METHODS: Eighteen pathologically confirmed diaphyseal osteosarcomas were reviewed. Images of X-ray (n=18), CT (n=12) and MRI (n=15) were evaluated by two radiologists. Differences among common radiologic findings of X-ray, CT and MRI, and between diaphyseal osteosarcomas and metaphyseal osteosarcomas in terms of tumor characteristics were compared. RESULTS: The common imaging features of diaphyseal osteosarcoma were bone destruction, lamellar periosteal reaction with/without Codman triangle, massive soft tissue mass/swelling, neoplastic bone and/or calcification. CT and MRI had a higher detection rate in detecting bone destruction (P=0.001) as compared with that of X-ray. X-ray and CT resulted in a higher percentage in detecting periosteal reaction (P=0.018) and neoplastic bone and/or calcification (P=0.043) as compared with that of MRI. There was no difference (P=0.179) in detecting soft tissue mass among three imaging modalities. When comparing metaphyseal osteosarcoma to diaphyseal osteosarcoma, the latter had the following characteristics: a higher age of onset (P=0.022), a larger extent of tumor (P=0.018), a more osteolytic radiographic pattern (P=0.043). CONCLUSION: As compared with metaphyseal osteosarcoma, diaphysial osteosarcoma is a special location of osteosarcoma with a lower incidence, a higher age of onset, a larger extent of tumor, a more osteolytic radiographic pattern. The osteoblastic and mixed types are diagnosed easily, but the osteolytic lesion should be differentiated from Ewing sarcoma. X-ray, CT and MRI can show imaging features from different aspects with different detection rates.