Whether a negative lifting sign is serious or not depends on the situation. It is more severe if the tumor is infiltrating into the submucosal layer, and less severe if the muscular bundles of the lamina propria are growing toward the mucosal layer.
The lifting sign is mainly observed after injecting a pad of water under the mucosa to see if the mucosal layer and the muscle layer are separated. If separation is possible, the lifting sign is positive; if separation is possible around the periphery and not possible in the center, it is positive as a central negative periphery; if separation is not possible at all, it is negative as a lifting sign.
The main reasons for a negative lifting sign are scar formation at the base of the ulcer, adhesions due to fibrosis of the underlying layers or inability to lift due to tumor entry into the submucosal layer or growth of muscle bundles of the intrinsic muscular layer toward the mucosal layer.
Negative areas of lesion are not lifted at all, and this condition is usually not amenable to endoscopic treatment with endoscopic mucosal dissection or tunneling techniques because of the potential for perforation or difficulty in dissection. Once this is the case, surgery is required.
The exact situation needs to be determined on the basis of pathologic tissue examination to determine the severity and to make the choice of therapeutic procedure.