Nontraumatic avulsions of the pelvis.

OBJECTIVE: The purpose of this report is to describe the imaging findings of nontraumatic avulsions of the pelvis. CONCLUSION: A diagnosis of avulsion fracture of the pelvis in an adult without appropriate history of substantial trauma must raise the suspicion of an underlying malignancy. If a patient has not been diagnosed as having a primary neoplasm, additional imaging evaluation is recommended. Also, biopsy may be considered in the proper clinical setting.