Inflammatory myofibroblastic tumor masquerading as perforated appendicitis

•Inflammatory myofibroblastic tumor can cause a presentation similar to perforated appendicitis.•Inflammatory myofibroblastic tumor should always be in the differential when a mesenteric mass is encountered.•Complete resection of inflammatory myofibroblastic tumor and follow-up treatment with NSAIDs help decrease the chance of recurrence.

Inflammatory myofibroblastic tumor (IMT) is a rare and histologically benign tumor that most commonly presents in pediatric patients. Abdominal IMTs often present with non-specific symptoms, and therefore they can masquerade as other more common abdominal conditions. This report describes two cases of IMT presenting as perforated appendicitis. Both cases are of young children who presented with over 48 hours of abdominal pain and who had peritonitis on examination. Pre-operative ultrasounds for both patients revealed complex free fluid. Laparoscopic evaluation demonstrated hemoperitoneum, and further exploration revealed mesenteric avulsion with abnormally thickened mesentery. Pathology confirmed IMT arising from the small bowel mesentery in both cases. Both children underwent limited bowel resection and were discharged in stable condition on a course of non-steroidal anti-inflammatory drugs (NSAIDs). Given the association of avulsed bowel to trauma, non-accidental trauma was suspected in both cases and demonstrated in one. Both patients showed complete resolution of tumor on follow-up MRI. The diagnosis of IMT must always be considered when an intra-abdominal mass is encountered as its treatment differs greatly from other neoplasms.