Focal infiltration of lymphoid tissue means that there is a localized lymphocytic infiltration at the time of pathological tissue biopsy, which generally suggests chronic inflammation or the presence of benign or malignant tumors. In chronic inflammatory conditions such as chronic gastritis and chronic hepatitis, inflammatory cells are usually manifested in localized inflammatory aggregates, with lymphocytic infiltration predominating. A moderate amount of lymphocytic infiltration can effectively remove pathogenic bacteria such as bacteria and promote the dissipation of inflammation. Chronic inflammation may occur with excessive lymphocytic infiltration. Benign tumors such as uterine smooth muscle tumors may cause the body to produce an immune response, causing lymphocyte infiltration, destroying cells adjacent to the tumor and blood vessel walls. When malignant tumors such as gastric cancer appear in the body, it will cause the body to produce a large number of lymphocytes, and lymphocytic infiltration will also occur when lymphocytes are invaded by malignant tumors. If lymphocyte focal infiltration is found in the examination, one should actively seek medical treatment and standardize the treatment.