Infected Urachal Cyst Masquerading as Acute Appendicitis on Point-of-care Ultrasound.

CASE PRESENTATION: A seven-year-old male presented to the pediatric emergency department with one day of abdominal pain. His physical exam was significant for rebound, guarding, and tenderness in the right lower quadrant, and his labs demonstrated a leukocytosis. Both a point-of-care ultrasound and radiology-performed ultrasound were concerning for acute appendicitis with a periappendiceal abscess, but on emergent laparoscopy the patient was found to have an infected urachal cyst.

DISCUSSION: Infected urachal remnants are a rare but important cause of pediatric abdominal pain. In this case, inflammation surrounding the patient's midline urachal cyst triggered a serositis that involved the appendix and pulled the cyst to the right. This created a clinical and radiologic presentation similar to appendicitis. This atypical presentation of an already rare anomaly highlights the importance of maintaining a broad differential during the work-up of pediatric abdominal pain.