Diffuse large B-cell lymphoma occurs in older individuals and frequently presents as localized disease with extranodal involvement, paicularly of the Waldeyer ring. The staining pattern indicates a B-cell proliferation (CD19, CD1O). T-cell (CD3) and monocytic (CD15) markers are absent, TdT can be expressed in B- lineage cells at an earlier stage of maturation. Small lymphocytic lymphoma is also a B-cell neoplasm, but it manifests with widespread lymphadenopathy, liver and spleen enlargement, and lymphocytosis, Lymphoblastic lymphoma is a T-cell neoplasm that occurs typically in the mediastinum of children. Reed-Stem berg cells characterize Hodgkin disease. In chronic lymphaderiitis, the lymph node has many cell types-macrophages, lymphocytes, and plasma cells. A monomorphous infiltrate is typical of non-Hodgkin lymphomas.