[Incidence and characterization of large-cell anaplastic lymphoma]

Large cell anaplastic lymphoma (LCAL) is a new entity among large cell lymphoma. Diagnosis is based upon morphology and on positivity to Ki1 antigen. The objectives of this study were: 1) to determine the incidence of LCAL in the patient population seen at the Instituto Roffo between 1981 and 1993; 2) to study the immunological phenotype; 3) to study the association with Epstein-Barr virus and HIV; 4) To study the expression of oncogen bcl-2 and 5) to evaluate tumoral growth factor.

The study was done on 1030 biopsies of nodal and extranodal lymphoproliferative diseases, with Hodgkin and non-Hodgkin lymphoma. Of the 1030 consecutive cases, 67 were selected. They revealed pleomorphic cells with sinusoidal disposition. Biotin and avidin peroxidase techniques were used to identify the following antigens: CD30(Ki 1), CD45RO (UCHL1), CD20(L26), CD45(CL), Epstein Barr virus (VEB), human immunodeficiency virus (HIV), CD15, CD68, PCNA, bcl-2 oncogen, vimentin, membrane epithelial antigen (EMA). Of these cases, only 10 revealed strong positive reaction to CD 30 (Ki1), thus they were considered to fulfill criteria to be classified as LCAL.

1. Incidence of LCAL in the lymphoma population under study was 1%. 2. Phenotype was B in 3 cases, T in 3, and macrophage in 1.3. There was 1 case of positive EBV and 3 positive HIV. 4. Eight of 10 LCAL cases were positive for bcl-2 protein. 5. Tumoral growth factor was 57%. Also, it was noted that most cases were secondary to Hodgkin lymphoma, and a few secondary to polymorphic immunoblastic lymphoma, with negative reaction to CD15 and EMA and positive for Vimentin.

1. Incidence of LCAL amongst patients with lymphoma is very low. 2. Immunological phenotype is varied. 3. There was no significant association with EBV or HIV. 4. Oncogen bcl-2 was demonstrated in most cases. 5. There was a high percentage of cells in proliferation.