Unusual case of intraluminal cecal recurrence of a low grade appendiceal mucinous neoplasm (LAMN)—Case report and brief literature review

INTRODUCTION: Appendiceal mucinous neoplasms exhibit a wide spectrum of clinical behavior, ranging from neoplasms which are relatively slow-growing but with considerable risk for recurrence and eventual death and those neoplasms that are highly aggressive with increased likelihood of early death. Clinical behavior depend mainly on mucinous neoplasms grading and staging. PRESENTATION OF CASE: We present the incidental finding of a mucinous appendiceal neoplasm in a 52 years old woman during her follow up for an operated breast carcinoma. The patient underwent appendectomy and a low grade appendiceal mucinous neoplasm (LAMN) confined into the appendiceal wall was diagnosed. Resection margin showed fibrous replacement of the appendiceal wall and some acellular intraluminal mucin. Three months later the tumor recurred inside the cecal lumen and a right hemicolectomy was performed showing again a LAMN confined into the bowel wall. DISCUSSION: According to the latest AJCC eighth edition patients with pTis LAMN, as in our case, (LAMN confined to the muscularis propria after histologic examination of the entire appendix) have essentially no risk of recurrence. Moreover, some authors suggest follow up for LAMN confined into the appendix even with a positive surgical margin. CONCLUSION: Rarely, LAMN may recur in the form of a polypoid protrusion into the cecal lumen and this recurrence may originate from the buried stump of the appendix, especially when the surgical margin is positive.