Cytological and histological classification of multiple myeloma

In a retrospective study of 202 cases of multiple myeloma (MM) were studied cyto- and histomorphologically. In 62 cases only bone marrow smears, in 60 only histological preparations and in 80 both types of material were available. According to the differentiation of myeloma cells, a plasmocytic (n = 127), a mixed cellular (n = 35) and a plasmoblastic type (n = 32) could be distinguished. Besides, 8 cases with predominance of giant cells were found (giant cell MM). The comparative cytological and histological typing into the four types of MM proved to be reproducible. The medium survival time and survival curves of the described types showed a statistically significant difference. The survival times were 39.7 months with the plasmocytic type, 16.1 months with the mixed cellular type, and 9.8 months with the plasmoblastic type. The prognostic relevance of the morphological classification was supported by the frequency of extramedullary infiltrates (20% in the plasmocytic, 67% in the mixed cell, 69% in the plasmoblastic and 100% in the giant cell type).