Perforated acute appendicitis resulting from appendiceal villous adenoma presenting with small bowel obstruction: a case report

BACKGROUND: A villous adenoma is an extremely rare benign tumour in the appendix, in contrast to other benign appendiceal lesions. The clinical features are usually asymptomatic. Acute appendicitis is the most common complication with the lesion obstructing the orifice of the appendiceal lumen. Thus, a villous adenoma is usually found during surgical intervention for acute appendicitis. Mechanical obstruction induced by acute perforated appendicitis has been previously reported. Acute appendicitis caused by a villous adenoma presenting with acute intestinal obstruction has not been previously reported. CASE PRESENTATION: A 78-year-old woman presented to our Emergency Department with diffuse abdominal pain and tenderness. The abdominal plain film and computed tomography revealed an intestinal obstruction. After surgical intervention, the ruptured appendix was shown to be associated with intestinal obstruction. The post-operative pathologic diagnosis was an appendiceal villous adenoma. CONCLUSIONS: This is the first report describing an appendiceal villous adenoma, which is an occasional cause of perforated acute appendicitis, presenting as a complete intestinal obstruction. We emphasize that in elderly patients without a surgical history, the occult cause of complete intestinal obstruction must be determined. If an appendiceal tumour is diagnosed, an intra-operative frozen section is suggested prior to selecting a suitable method of surgical intervention.