Low-grade Appendiceal Mucinous Neoplasm in the Context of Acute Appendicitis.

A 49-year-old woman presented with clinical signs, pre-operative imaging, and intra-operative findings suggestive of acute appendicitis. A laparoscopic appendectomy was performed. Final pathology revealed a low-grade appendiceal neoplasm with serrated architecture, and secondary acute inflammation of the appendix (5 cm in length x 0.7 cm in diameter) with a congested and hemorrhagic serosal surface. The main concern in the management of patients with low-grade appendiceal mucinous neoplasm (LAMN) is that these dysplastic tumors share such similar clinical, imaging, and intraoperative features with simple acute appendicitis, which is deemed definitively cured following surgical removal of the appendix. A definitive diagnosis of LAMN is often delayed until the final pathology report; however, this finding can have implications on the further management of the patient, especially with the risk of recurrence in situations of peritoneal dissemination or positive surgical margins. Reporting LAMN cases will increase awareness of this rare disease and will contribute to improved management in the future.