Immunoblastic sarcoma of T-cell versus B-cell origin: I. Clinical features.

Within the Lukes-Collins classification system of malignant lymphoma, a tumor of large transformed lymphocytes, termed immunoblastic sarcoma (IBS), is described. This morphological type would have been included within the "histiocytic" category of Rappaport. Immunoblastic sarcoma may be of B-lymphocytic or T-lymphocytic origin. Since differences or similarities of these two variants have not yet been described, we reviewed the case histories of 35 such patients, all of whom had immunologic marker studies performed. Nineteen patients had T-cell IBS (T-IBS), whereas 16 had B-cell IBS (B-IBS). Median age for both groups was approximately 50 yr. A history of prior immune disorder was found in 31% of B-IBS and 16% of T-IBS cases. Prior lymphoproliferative malignancy was noted in 21% of T-IBS and 13% of B-IBS patients. All T-IBS patients first presented because of lymphadenopathy, whereas 56% of B-IBS cases initially presented because of extranodal disease. Systemic "B" symptoms were common in both. Similarly, most patients had widespread disease (stage III or IV) at diagnosis. Clinically suspected hepatic (p = 0.05) and retroperitoneal node (p = 0.01) involvement were more often found in T-IBS. Forty-one percent of T-IBS patients demonstrated polyclonal hypergammaglobulinemia, a finding seen in no B-IBS patient (p = 0.02). Although not statistically significant because of small numbers of patients, data on therapy and survival suggest that IBS of B-cell type may be successfully treated with aggressive, multiagent chemotherapy, while alternative approaches appear warranted in T-cell disease.