Radiographic features of low-grade central osteosarcoma / 中华放射学杂志

ABSTRACT

Objective To explore the imaging manifestations of low-grade central osteosarcoma (LGCOS) and discuss their pathological features.Methods Twelve patients of LGCOS proved by surgery and pathology were analyzed retrospectively and a review of related literature was performed.All twelve patients had plain X-ray,1 1 patients CT examination,and 10 patients contrast-enhanced MR scan.Imaging features of the LGCOS were summarized,their clinical and pathological manifestations were discussed for differential diagnosis.Their prognosis was evaluated with followed up examination.Results Of the 12patients with LGCOS,six tumors were located in the distal femur,3 in the proximal tibia,2 in the proximal femur and 1 in the talus.The radiographic features of LGCOS were variable.There were 7 patients with predominantly osteolytic destruction,3 patients with mixed sclerotic and lyric changes,with well-defined margins,2 patients with Osteogenic changes on X-ray.On CT,9 patients showed a clear cortical breach,5 patients with soft tissue involvement,6 patients with peripheral incompletely sclerotic zone,2 patients with periosteal reaction.On MRI,there were 10 patients with abnormal signal in medullary cavity,8 patients with soft tissue masses,and all 10 patients exhibited contrast enhancement.The microscopic features of LGCOS were characteristically bland,comprising spindle cells arranged in interlacing fascicles in a heavily collagenous background with variable bone or osteoid production.There were mild nuclear atypia and rare mitoses.In four patients,misdiagnoses were made by biopsy or surgical pathology as fibrous dysplasia or fibrous histiocytoma and other benign lesions,all four patients had postoperative recurrence.Conclusions LGCOS should be differentiated form fibrous dysplasia,non-ossifying fibroma,and other benign lesions.An accurate diagnosis can be made in most cases by careful pathological and radiological correlation.