The L1 type is characterized by small (10- to 15- μ ) cells, with round, finely reticulated to coarse chromatin, some nuclear indentation, sparse slightly basophilic cytoplasm, and absent nucleoli. L1 lymphoblasts are distinguished from normal mature lymphocytes by the homogeneity in their chromatin structure and their monotonous appearance. FAB = French-American-British.
By permission of the publisher. From Cortes J, Albitar M. In Atlas of Cancer . Edited by M Markman and M Kalaycio. Philadelphia, Current Medicine, 2002.