Appendiceal agenesis in a 3-year-old boy presenting with suspected acute appendicitis: a case report

Appendiceal agenesis is a rare congenital gastrointestinal anomaly, usually discovered unexpectedly during surgery for suspected acute appendicitis. It cannot be diagnosed pre-operatively by clinical, laboratory or imaging findings, and final confirmation requires thorough surgical inspection of the ileocecal region. We report a 3-year-old boy with 38-hour intermittent abdominal pain, bilious vomiting and fever suggestive of acute appendicitis. Pre-operative CT failed to visualize the appendix but showed pericecal inflammation and enlarged mesenteric lymph nodes. Laparoscopy combined with limited open laparotomy confirmed Collins Type-III appendiceal agenesis (complete absence of the appendix with an intact caecum), accompanied by localized peritonitis and intra-abdominal adhesions. Mesenteric lymph node biopsy revealed reactive lymphadenopathy, excluding granulomatous or neoplastic lesions. The child had an uneventful postoperative recovery and was discharged in satisfactory condition. This case highlights that appendiceal agenesis should be included in the differential diagnosis when the appendix cannot be located intra-operatively, and surgeons should adhere to standardized exploration protocols before establishing this diagnosis.