Conclusions
In conclusion, ballooning of bone, cyst in long bone, male sex, thin cortical thickness and multilocular cyst were significant adverse prognostic factors for pathological fractures, whereas fracture at presentation and history of biopsy were favorable prognostic factors for healing of UBC in patients under observation. These clinical factors may be useful for deciding treatment in patients with UBC. A history of mechanical disruption of UBC such as fracture and biopsy seems to be good indication for watchful waiting, but patients with some poor prognostic factors of fractures or with UBC in the femur should be treated with surgery.