CHARACTERISTIC CLINICOPATHOLOGICAL FEATURES OF ADULT B-CELL LYMPHOBLASTIC LYMPHOMA WITH SPECIAL EMPHASIS ON DIFFERENTIAL-DIAGNOSIS WITH AN ATYPICAL FORM PROBABLY OF BLASTIC LYMPHOCYTIC LYMPHOMA OF INTERMEDIATEDIFFERENTIATION ORIGIN

Background. Lymphoblastic lymphoma is typically of thymic T-cell pheno type. Lymphoblastic lymphoma of B-cell origin (B-lymphoblastic lymphom a) has been relatively poorly described. Whether B-lymphoblastic lymph oma should be managed like its T-cell counterpart remains to be clarif ied. Methods. From 1933 to 1991, 10 adult patients were diagnosed as h aving B-lymphoblastic lymphoma at National Taiwan University Hospital by using the histomorphologic criteria of international working formul ation. B-cell phenotype was determined by the immunohistochemistry met hod. Clinicopathologic features of these 10 patients were reviewed. Re sults. Seven patients were grouped as typical type and were characteri zed by an aggressive clinical course with lymph node (7 of 7), bone ma rrow (6 of 7), liver (3 of 7), spleen (3 of 7), and central nervous sy stem (2 of 7) involvement. The median survival time was 8 months. In c ontrast, three patients had an atypical clinical picture. They were ol der patients (64-73 years) and were characterized by a relatively less aggressive course with predominantly bulky nodal involvement. Two of these three patients are alive (31 and 49 months, respectively) and we ll at this report, with one of them being repeatedly experiencing dise ase remission with the use of simple salvage chemotherapeutic regimens . Further studies revealed that tumor tissues of these three atypical cases had strong expression of CD5 (Leu-1) marker. Conclusion. B-lymph oblastic lymphoma diagnosed by histomorphologic criteria should be fur ther distinguished from a relatively favorable subtype, which probably represents a variant of blastic lymphocytic lymphoma of intermediate differentiation as described by Lardelli et al.(1) Clinical features o f typical B-lymphoblastic lymphoma, except for the lack of mediastinal involvement, is similar to its T-cell counterpart.