Histopathologic analysis of the so-called secondary blastic non-Hodgkin's malignant lymphomas.

Fifteen cases of blastic transformation of originally low grade malignant lymphomas to high grade malignant ones were studied. The material was selected from the biopsy registry of our institute and had been collected over the period of 1 January 1982 to 1 March 1984. In 10 cases this transformation was verified morphologically (in 8 cases by successive biopsies, in 2 cases in the sectional material). At the time of the first biopsy, transformation was suspected in four cases. There were 4 cases of transformation of centroblastic-centrocytic lymphomas to centroblastomas, one case of centrocytoma transformed to centroblastoma, two cases of immunocytomas transformed to centroblastomas, and three cases of immunocytomas transformed to immunoblastomas. The transformation took place within a mean time of 9.5 months after the first biopsy, and 6 patients died, on the average, within 5.3 months after the rebiopsy. In live cases only 1 bioptic examination was done on the basis of which the blastic transformation has been suspected, though not proved yet. There was one case of a suspected transformation of a centroblastic-centrocytic lymphoma to a centroblastoma type with structural remnants of low grade malignant lymphomas, in one case the In the further two cases there were blastic malignant lymphomas of the centroblastoma type with structural remnants of low grade malignant hymphomas, in one case the centroblastic-centrocytic type, in the other the immunocytic lymphoma type. The morphological criterion for a suspected rise of a secondary blastic lymphoma is the presence of clear regions composed of an accumulation of blasts with increased mitotic activity in the prevalent structure of the low grade malignant lymphoma.