Computed tomography in the diagnosis of gluteal abscess and other peripelvic fluid collections.

During an 18 month period, five patients of all those being investigated by computed tomography (CT) for suspected abscess were found to have localized peripelvic extraabdominal fluid collections. In three, this was due to primary abscess or pyarthrosis and to probable secondary infection of a degenerated hematoma or seroma in two. The lesions were responsible for or considered contributory to the patient's febrile illness in each case. The collections were inconspicuous or poorly localized clinically but readily apparent on CT. Treatment by CT guided needle aspiration or operative drainage was performed in each patient and was followed by relief of symptoms and fever.