ObjectiveTo explore the clinical characteristics of pathological fracture in extremities caused by bone tumors or tumor-like lesions. MethodsFrom August 2002 to December 2010, 139 patients with pathological fractures were entered in the study, including 79 males and 60 females with an average age of 31.1 years. Fractures included tumor-like lesion in 55 cases, benign tumor in 13, giant cell tumor (GCT)in 7, primary malignant tumors in 28, and metastatic tumors in 36. Forces induced to fractures were classified into four grades: spontaneous fracture, functional activity, minor injury, severe injury. Age, fracture location, histological results, fractures forces, prodromes, and misdiagnosis were all observed. Chi-square test were use to compare forces and prodromes within different tumors. ResultsThe highest morbidity rate is 32.4％(45/139) which lies in 11-20 years old. The cites of fractures including femurs in 71 cases, humerus in 36, tibia in 15, fingers in 7, radiuses in 4, fibula in 3, ulnas in 2, and metatarsus in 1. Fracture forces include spontaneous fractures in 29 cases, functional activity in 42, minor injuries in 65, and traumatic injuries in 3. Sixty-seven patients(48.2％) had local prodromes. The prodromes of both malignant tumors and metastatic tumors were more than benign tumors. Twenty cases experienced misdiagnosis with average delay time of 12 weeks. ConclusionMinor injury forces and local prodromes are clinical key features of pathological fractures. Both of them are key points of avoiding misdiagnosis.