Newly recognized variant forms of non-Hodgkin's lymphomas.

High-resolution ancillary diagnostic methods, in concert with conventional histomorphology, have allowed recognition over the past 8 years of distinct clinical-pathologic variants of non-Hodgkin's lymphomas. With the insights previously offered by these studies, the pathologist can establish, or at least strongly suggest, the diagnosis of these entities on the basis of conventional histomorphology alone. As always, clinical information is essential for arriving at the correct diagnosis. Allocation of a rapidly frozen block of tumor tissue is a convenient, reliable "insurance policy" for the optional application of immunophenotyping and, if necessary, genetic probe analysis to resolve unusual or subtle subclassification problems. Because of clinical management implications, hematologists and oncologists should be aware of these newly recognized variant forms of non-Hodgkin's lymphomas.