Lymphoblastic lymphoma/leukemia of T-cell origin: ultrastructural, cytochemical, and immunologic features of ten cases.

Ten cases of T-lymphoblastic lymphoma/leukemia were studied with light and electron microscopy. Cytochemical strains were performed on touch preparations, and mononuclear cell suspensions were tested for spontaneous rosette formation with sheep erythrocytes, C3 receptors, and surface immunoglobulins. The present investigation was performed to evaluate several ultrastructural parameters, mainly the nuclear shape, as diagnostic clues for this group of lymphomas. Characteristic convoluted nuclei were present in 7 to 47% of the lymphoblasts. This percentage correlated with the focal acid phosphatase reaction and E-rosette formation. Acid phosphatase was the best cytochemical marker (70-100% of the lymphoblasts showed focal reaction product). By ultrastructural cytochemistry, the reaction product was demonstrated in the Golgi cisternae and primary lysosomes. The cell suspensions obtained from different sources contained 14 to 95% E-rosette-forming cells. No specific morphologic, cytochemical, or immunologic differences were found between patients with or without mediastinal involvement.