Stereologic analysis of the ultrastructure of isolated human T and non-T lymphoid cells. III. Studies in chronic lymphoid leukemias, hairy cell leukemia and some malignant lymphomas.

Abstract

Malignant cells from 9 cases of chronic lymphocytic leukemia (CLL), 4 cases of prolymphocytic leukemia (PLL), 4 cases of hairy cell leukemia (HCL), 4 cases of malignant lymphoma of centrocytic type and 3 cases of malignant lymphoma of lymphoblastic type (Kiel classification), all examined for T and B markers, were analysed by electron microscopy. Stereological methods were applied to assess relative and absolute values concerning the whole cell and nuclear and cytoplasmic components of the average cell in each population, and comparisons were made between the morphologically and immunologically defined subsets. The CLL-lymphocyte possessed the smallest cell volume, a high nucleo-cytoplasmic volume ratio, densely packed heterochromatin, a small nucleolar volume and a sparse Golgi complex. The 7 B-derived cases were characterized by a larger volume of rough ER and a more irregular plasma membrane than the two T-derived cases, which typically displayed dense granules in paranuclear aggregations. The prolymphocyte could be distinguished from the CLL-cell by its larger cell volume, lower nucleo-cytoplasmic volume ratio, proportionally lesser heterochromatin, typically condensed at the periphery and around a prominent nucleolus. All 4 cases of PLL were of B-nature and shared the features of B-CLL regarding increased rough ER and low content of granules. The hairy cell exhibited the largest cell volume, the lowest nucleo-cytoplasmic volume ratio, an indented nucleus and a remarkable irregular cellular surface with long "hairy" processes. The cytoplasmic inclusions of ribosome-lamella complexes were recorded exclusively in hairy cells, in half of the patients. The centrocyte was characterized by a cell volume of intermediate size, a high nucleo-cytoplasmic volume ratio and the highest degree of nuclear irregularity recorded. The amount of rough ER was considerably less than in B-CLL and B-PLL. Finally, the blast from the cases of lymphoblastic lymphoma, all of T-nature, displayed a smooth plasma membrane, a high euchromatin-heterochromatin volume ratio and dense granules, characteristically clustered in the vicinity of the Golgi complex. Stereology on the ultrastructure of malignant lymphoid cells provides a more accurate characterization and may be helpful in classification.