Unveiling Neonatal Appendicitis: A Unique Case of Chronic Appendicitis With Fibrosis and Cystic Mass Presentation.

Neonatal appendicitis is a rare condition, with limited comparable case reports and studies available in the literature. Clinical presentation can be variable, but typically includes abdominal distension, fever, decreased feeding, and vomiting. This case study describes a previously healthy 21-day-old female who presented to the emergency department with a one-day history of abdominal distension and decreased feeding. Imaging, including abdominal X-ray, ultrasound, and MRI, demonstrated a cystic mass in the right lower quadrant of unclear etiology. Exploratory laparotomy revealed a gelatinous, bilobed cystic-appearing mass located deep to a loop of small bowel in the right lower quadrant, necessitating an ileocecal resection. Histopathology demonstrated foci of acute inflammation with abscess formation, necrosis, and a surrounding exuberant fibroblastic reaction. This case contributes to the limited understanding of neonatal appendicitis and offers valuable insight into its presentation, imaging findings, and surgical management.