Multiple myeloma: significance of plasmablastic subtype in morphological classification.

We classified 100 cases of myeloma before chemotherapy as mature (28), intermediate (38), immature (19), or plasmablastic (15). The plasmablastic group had an estimated median survival (Kaplan-Meier method) of ten months, compared to 35 months for the other types (P less than .05). Decreased survival in the plasmablastic group was due to more frequent deaths in the first six months. There were no significant differences in survival among the mature, intermediate, and immature groups or among patients with different morphological grade or asynchrony scores. The plasmablastic myeloma group had more frequent renal insufficiency and higher plasma cell labeling indices, which may have contributed to the shorter survival.