Preoperative sonographic diagnosis of McSwain type V appendiceal intussusception: A case report (with video)

Appendiceal intussusception is a rare disease. The definite preoperative diagnosis of appendiceal intussusception is rare and challenging. Here, we present a case of McSwain type V appendiceal intussusception in a 10-year-old boy. To our best knowledge, this is the first case report of a type V appendiceal intussusception that was preoperatively confirmed with sonography. Here, we have described in detail the ultrasound features and differential diagnosis of this rare disease.

A 10-year-old boy presented with 3 days of recurrent intermittent mild abdominal pain. The result of ultrasonography suggested an ileocolic intussusception and a therapeutic air-contrast enema was requested to reduce the intussusception but failed at a local hospital.

Physical exam revealed mild tenderness in the lower right quadrant of the abdomen. However, ultrasonography showed a target-sign in cross section and a finger-like appearance in the longitudinal view. A diagnosis of McSwain type V appendiceal intussusception was made.

The patient underwent an appendectomy after successful manual reduction on laparotomy. The appendix was successfully resected.

Intraoperatively, the appendix was completely inverted in the cecum, and the preoperative sonographic findings were confirmed. During follow-up, there were no signs of recurrence.

Pre-operatively, on ultrasound a type V appendiceal intussusception is usually misdiagnosed as an ileocolic intussusception. Radiologists must execute caution to avoid over reliance on the sonographic findings of intussusception, especially when there is a mismatch with clinical symptoms. It is especially important to accurately understand the surgical-anatomic configuration of type V appendiceal intussusception that creates a "target-sign" and a "finger-like" layout on ultrasonography.