Malignant lymphoma of lymphoplasmacytic/lymphoplasmacytoid and immunoblastic types

Sixty-four patients with extranodal non-Hodgkin's lymphomas of lymphoplasmacytic/lymphoplasmacytoid (LP) and immunoblastic (IBS) types were reviewed. The criteria distinguishing the latter from the former was a presence of basophilic and prominent nucleoli in a vast majority of the tumor cells. The numbers of LP and IBS types were 34 and 30, respectively. Intervals from appearance of tumors to initial treatment in LP and IBS were 15.7 +/- 25.3 and 6.0 +/- 12.3 months, respectively (p less than 0.1). Histologically LP had a low mitotic count (p less than 0.001) and contained a larger number of mast cells (p less than 0.05) than IBS. Proliferating cells in 4 patients with LP type had nuclei with a slightly irregular indentation similar to those of intermediate lymphocytic lymphoma. Follow-up study revealed the LP type to have a much more favorable prognosis than the IBS type (p less than 0.001) though 3 patients with LP showed unfavorable prognosis. Tumor cells in these tumors had a small to medium-sized, often convoluted nucleus. The present results showed that the distinction of LP and IBS by their morphology of nucleoli was prognostically meaningful. Furthermore it is suggested that tumors of the LP type are heterogeneous.