A rare trigger for acute appendicitis leading to small bowel obstruction: traditional serrated adenoma of the appendiceal foramen

This is the first documented case of traditional serrated adenoma (TSA) of the appendiceal foramen that triggered acute appendicitis resulting in small bowel obstruction (SBO). An 88-year-old Japanese man presented with abdominal pain, distension, and appetite loss. Computed tomography demonstrated distended ileum adherent to cecum with thickened walls. He was diagnosed with SBO, and open ileoceal resection was eventually performed. Pathological examination revealed that a pedunculated polyp had obstructed the appendiceal foramen and triggered acute appendicitis, thus leading to SBO. Histopathological examination of the polyp revealed that the long fronds of the adenoma were lined by dysplastic epithelial cells, which is a characteristic feature of TSA. This case report illustrates that a tiny TSA can trigger the obstruction of the appendiceal foramen and lead to acute appendicitis and SBO. We underline the need for the resection of the polyps in this region regardless of their size.