Tumors located in the rectum (HR = 2.362, 95% CI: 1.449–3.851, p = 0.001) and with CEA > 5 (HR = 2.583, 95% CI: 1.581–4.219, p < 0.001), CA19-9 > 37 (HR = 3.587, 95% CI: 1.958–6.573, p < 0.001) and mutant KRAS (HR: 1.991, 95% CI: 1.113–3.564, p = 0.020) were more likely to have synchronous LM than tumors with other features. Here, KRAS is linked to lymphangioma.