Unicameral bone cysts of the pelvis: a study of 16 cases

Unicameral bone cysts of the pelvis are extremely rare. This study summarizes the clinical, radiologic and pathologic features of 16 cases. Patients ranged in age from nine to 69. Most lesions were in the anterior portion of the iliac wing; many appeared to be related to an open iliac crest apophysis. This suggests that the pathogenesis of unicameral bone cysts in this portion of the ilium is similar to that seen in the proximal humerus and the proximal femur. The correct diagnosis was made preoperatively in only five cases. This indicates that, although they are well documented, unicameral bone cysts of the pelvis remain a diagnostic problem. Patients received a spectrum of treatments from curettage to observation. There appeared to be no difference in the outcome after any form of treatment. Therefore, unicameral bone cysts of the pelvis can be managed conservatively. The choice to manage patients conservatively depends on making the correct diagnosis based on clinical history and imaging. The most effective imaging is a combination of plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI).