A middle aged woman was investigated for right sided abdominal pain and fevers. She had a past history of rheumatoid arthritis and was on long term steroids. An abdominal ultrasound was ordered to look for the source of her fever.
Gallstones were found as an incidental finding (see case)
When examining the right iliac fossa a mass was noted. In the transverse plane, an irregular hypoechoic area was seen adjacent to the swollen psoas muscle. In the longitudinal plane the mass extended along the psoas to the inguinal crease.
The gallstones were an incidental finding. The swollen psoas muscle with the irregular hypoechoic area suggested a psoas abscess which was confirmed on CT.