Histologic sections of lymph node demonstrate partial effacement of normal architecture by a nodular proliferation of very irregular follicular structures which contain large transformed cells, abundant mitoses, many apoptotic bodies, and many large vacuolated spaces of variable size. The abnormal follicles are divided into multiple fronds by mantle zone type lymphocytes. Some follicles show greater degrees of necrosis. Occasional eosinophils are noted in perifollicular areas. One relatively small but prominent area adjacent to a follicular structure displays an atypical spindle cell proliferation. Other areas of the interfollicular region show areas of probable extension of cells from atypical follicles, with many small lymphocytes and areas of sclerosis. Focally, the architecture of the lymph node is preserved, with hyperplastic appearing, otherwise normal germinal centers.