Among them, the carcinoembryonic antigen (CEA) marker demonstrates the highest diagnostic accuracy in discriminating between mucinous cyst (MC) and non-mucinous cyst (NMC)13, 14, 15, and in a large multicenter study16, demonstrated 77% specificity and 61% sensitivity at a cutoff value of 192 ng/mL cyst fluid CEA. Here, CEACAM5 is linked to nut midline carcinoma.