Ileocecal and appendiceal intussusception associated with typhlitis in a child with medullary aplasia: A case report.

Appendicular intussusception is a rare form of intestinal intussusception where the appendix itself invaginates into the adjacent cecum or colon. It accounts for a small percentage of all intussusception cases, most commonly affecting children. Its association with ileocolic intussusception, particularly in the context of mural thickening caused by typhlitis, is even more uncommon. We present a 9-year-old boy with medullary aplasia who developed diffuse abdominal pain, vomiting, and dark stools. Laboratory results showed pancytopenia, and imaging revealed significant circumferential thickening of the cecum, ascending colon, and terminal ileum on abdominal ultrasound. The ultrasound also showed ileal intussusception into the cecum, with mesenteric lymphadenopathy and free intra-peritoneal fluid. Contrast-enhanced CT confirmed ileocolic intussusception with an appendiceal intussusception, classified as McSwain's grade V. The CT also revealed wall thickening and submucosal edema in the affected bowel segments, along with multiple mesenteric lymph nodes and moderate free fluid. These findings were consistent with ileocolic intussusception secondary to typhlitis in an immunocompromised child. This study aims to highlight the imaging features of ileocolic and appendicular intussusception in a pediatric patient.