RT Journal Article SR Electronic T1 Endometriosis presenting like a psoas abscess JF Saudi Medical Journal JO Saudi Med J FD Prince Sultan Military Medical City SP 952 OP 954 VO 28 IS 6 A1 Bhat, Shyamasunder N. A1 Mohanty, Simanchal P. A1 Kustagi, Prahlad YR 2007 UL http://smj.org.sa/content/28/6/952.abstract AB Endometriosis is the presence of ectopic endometrial tissue that responds to hormonal stimulation. Although endometriosis occurs most often in the pelvis, several unusual sites have been reported. We present a case of endometriosis mimicking, a psoas abscess. A 39-year-old lady presented with pain around the right hip, of 5 years duration. Computed tomography CT scan showed a multi-loculated mass in the right iliopsoas muscle. On exploration, a hemorrhagic cystic mass was seen pressing on the femoral nerve. The lesion was excised and histological examination of the tissue showed features of endometriosis. The patient was treated by cyclic hormonal suppressive therapy for 3 months. Her pain and the flexion deformity of the hip resolved completely. Retroperitoneal endometriosis presenting with deformity and pain in the hip may mimic a psoas abscess. If the possibility of this diagnosis is entertained, inappropriate treatment may be avoided.