Intracytoplasmic immunoglobulins in the differential diagnosis of lymphocytic lymphomas of the B-CLL type and immunocytic lymphomas.

One hundred and thirty-three consecutive cases originally classified either as a lymphocytic lymphoma of the B-CLL type or as an immunocytic (IC) lymphoma could be reclassified morphologically and analyzed for the presence of cytoplasmic immunoglobulins (cIg) with the PAP-technique. The morphologic reclassification confirmed the initial diagnosis in most cases, whereas after staining for cIg, the diagnosis was changed in a large number of cases, i.e. from B-CLL to IC, or the reverse, or from IC of the polymorphic subtype (ICp) to 'high-grade' non-Hodgkin lymphoma (NHL). Cases classified as IC were often localized (stage I+II: 22/43) with a long disease-free survival after local radiation therapy, while B-CLL were usually generalized. For patients in stage IV, the prognosis of B-CLL was significantly superior to that of IC, which in turn was superior to the prognosis of cases referred to as 'high-grade' NHL. The difficulties in the morphologic distinction between B-CLL and IC on one hand and between ICp and some 'high-grade' NHL on the other hand, as well as the clinical significance of these distinctions, are discussed.