Co-Occurrence of Submucosal Schwannoma and Low-Grade Mucinous Neoplasm in the Appendix, a Clinical Conundrum : A Case Report

Two and more types of tumors rarely occur in the appendix, a constrained space of the human body. We experienced a rare co-occurrence of schwannoma and low-grade mucinous neoplasm (LAMN) in the appendix and obtained a lesson to scrutinize the radiological images in the follow-up period. A computer tomography (CT) performed for surveillance of bile duct stone of a 68-year-old man incidentally detected the appendiceal tumor, which characteristics were not clear at that time, 1-year before admission because of epigastric pain due to acute cholecystitis. CT showed enlargement of tumor in the appendix, and laparoscopic ileocecal resection and cholecystectomy were performed under the diagnosis of acute cholecystectomy and appendiceal tumor. Histopathological examination revealed two types of appendiceal tumors, schwannoma and low-grade appendiceal neoplasm. To the best of our knowledge, co-occurrence of schwannoma and LAMN has never been reported and this complicated our interpretation of clinical images during the course. We report a clinical lesson in handling this rare combination of tumors in the appendix with the relevant literature.