Systemic anaplastic large-cell lymphoma: Results from the non-Hodgkin's lymphoma classification project

Anaplastic large-cell lymphoma (ALCL) is a heterogeneous process that may h ave a T-cell, B-cell, or indeterminant (null) phenotype and which may or ma y not express the anaplastic lymphoma kinase (ALK) oncoprotein. Because the clinical significance of these variants of ALCL is unclear, we evaluated t he cases of ALCL-T/null and ALCL-B identified in the Non-Hodgkin's Lymphoma Classification Project. We evaluated 1,378 cases of non-Hodgkin's lymphoma (NHL), and a consensus diagnosis of ALCL-T/null was made in 33 patients (2 .4%) with a diagnostic accuracy of 85%. Compared to 96 patients with other forms of peripheral T-cell lymphoma (PTCL), those with ALCL-T/null were sig nificantly younger, less likely to have advanced-stage disease or bone marr ow involvement, more likely to have a low International Prognostic Index sc ore, and had a significantly better survival. Among those with ALCL-T/null, there were no significant differences in the clinical features or survival on the basis of ALK expression. A consensus diagnosis of ALCL-B was made i n 15 patients (1.1%), and the diagnostic accuracy was 67%. However, compare d to 366 patients with other forms of diffuse large B-cell lymphoma (DLBCL) , those with ALCL-B were no different with regard to clinical features or s urvival. We conclude that patients with ALCL-T/null have favorable prognost ic features and excellent survival and should be separated from those with other forms of PTCL for prognostic and therapeutic purposes. In contrast, p atients with ALCL-B appear to be similar to those with other forms of DLBCL . (C) 2001 Wiley-Liss, Inc.