According to the 2010 WHO classification, LAMNs are mainly noninvasive epithelial lesions that generally present with mucin accumulation in the lumen of the appendix.[5] Additionally, a LAMN is considered a precursor to appendiceal mucinous adenocarcinoma and is characterized by mucin accumulation within the appendix, often without invasion into surrounding tissues. The gene discussed is MUC5AC; the disease is colon mucinous adenocarcinoma.