Endoscopic Appearance of Benign Versus Malignant Appendiceal Mucocele

Abstract

Introduction: Appendiceal mucoceles are group of rare non-neoplastic or neoplastic cystic lesions characterized by an enlarged, mucus-filled appendix. Here we present two cases of incidentally found benign and malignant mucoceles. Case 1: A 62-year-old male underwent screening colonoscopy. He denied any gastrointestinal symptoms. Physical exam was unremarkable. The colonoscopy exam was normal except for a glossy, rounded, protruding mass arising from the appendiceal orifice that didn't flatten with air insufflations (Fig. 1-A). Overlying mucosa was normal. Probing with the biopsy forceps revealed a hard lesion. The biopsy revealed normal mucosa. Abdominal computed tomography (CT) scan showed a low attenuation, wellencapsulated round cystic mass in the right lower quadrant adjacent to the cecum with no other abnormalities (Fig. 1-B). The patient was diagnosed with appendiceal mucocele and underwent laparoscopic appendectomy. Intraoperative evaluation and surgical pathology confirmed the diagnosis of benign appendiceal mucocele (Fig. 1-C).Figure 1Case 2: 70-year-old Caucasian male with history of Barrett's esophagus was recently diagnosed with welldiff erentiated adenocarcinoma of the esophagus. As a part of tumor staging, he had abdominal CT scan which incidentally revealed cystic mass in the right lower quadrant adjacent to the cecum. So the patient underwent colonoscopy which showed ulcerated mass involving the appendiceal orifice measuring 1.5 cm in diameter (Fig. 2). The mass was highly suspicious for malignant mucocele. Multiple biopsies were obtained. The rest of the colon examination was not significant. Histopathology exam showed adenocarcinoma. The patient was referred for evaluation by multidisciplinary oncology team for further evaluation of the malignant esophageal and malignant appendiceal mucocele.Figure 2Conclusion: The diagnosis of appendiceal mucocele can be suspected during colonoscopic exam of the appendiceal orifice. Mucosal ulceration favors the diagnosis of malignant rather than benign appendiceal mucocele.