An elderly man on warfarin presented because of a tender mass in his low abdomen. Examination also revealed a further mass in his right iliac fossa which was less distinct.
There is a complex cystic structure within the anterior abdominal wall. This contains thick septations and fluid levels suggestive of a liquifying haematoma. The mass is above the peritoneal line and is continuous with the rectus muscle (not shown).
In addition a large, simple cystic structure was noted in the right iliac fossa. This structure was within the peritoneal cavity (as shown by the bowel above the mass). The cause of this mass was uncertain on ultrasound.
An abdominal CT was performed to further investigate the pelvic mass, which was thought to be a mesenteric cyst (the differential was an old, liquified haematoma). The patient's need for anti-coagulation was reviewed and his warfarin ceased.
Rectus sheath haematomas can mimic intra-abdominal pathology due to their local tenderness and pain. Failure to diagnose can result in unnecessary laparotomy.