Ill-defined abnormal low T1 / high T2 signal throughout both iliac bones, right greater than left, with associated patchy postcontrast enhancement. No large extra-osseous mass. On the right, the signal change abuts the right sacro-iliac joint without joint destruction, effusion or extension into the sacrum. Periosteal enhancement and fluid surrounds the signal change in both iliac bones extending around the iliacus muscles bilaterally as well as along the posterolateral aspect of the right psoas major muscle. No further focal osseous lesions.
Pelvic viscera are within normal limits. No pelvic free fluid. No enlarged pelvic sidewall or inguinal lymph nodes. Femoral neurovascular bundle is normal. No inguinal or femoral hernia.