Abstract

Richter's syndrome is generally accepted taht lymphoma or leukemia of low grade malignancy, during their course, may alter both their morphologic and clinical appearance and evolve into highly malignant neoplasia. The pathogenesis is not clear, however, dedifferentiation by the emergence of a new clone of cells of higher maligancy similar to the blastic transformation in chronic myelocytic leukemia is suggested as possible mechanism. A case of Richter's syndrome is described. This 45 year old female had been diagnosed as chronic lymphocytic leukemia by absolute peripheral lymphocytosis 5 months before, developed sudden severe abdominal pain and was received segmental resection of ileum under the clinical impression of intestinal perforation with peritonitis. Histologically, the ulcer margin was diffusely infiltrated by polymorphic cells composed of large atypical cells having vesicular nuclei, multinucleated giant cells and Reed-Sternberg like cells admixed with mature lymphocytes. These atypical and multinucleated cells of the paraffin section showed strong monoclonal immunoreactivity for IgG and lambda light chain by PAP method and was interpreted as malignant lymphoma, diffuse, large cell, immunoblastic, polymorphous.