Clonal ambiguity of human immunodeficiency virus-associated lymphomas. Similarity to posttransplant lymphomas.

Initial biopsy specimens from two patients with lymphadenopathy and human immunodeficiency virus antibody-positive serum presented considerable difficulty in making specific histologic and immunologic diagnoses, although subsequent biopsy specimens revealed clear progression to acquired immunodeficiency syndrome (AIDS)-associated lymphomas. The initial biopsy specimens revealed multifocal clusters of large blastic lymphoid cells, with some clusters showing a monoclonal lambda light chain predominance, whereas other clusters showed a kappa predominance, indicating considerable phenotypic ambiguity suggestive of polyclonality. This initial clonal ambiguity was followed within two to three months by overt histologic, phenotypic, and clinical malignant transformation to a diffuse high-grade monoclonal B-cell lymphoma. These data have significant implications for the clonality and pathogenesis of AIDS-associated lymphoproliferative disorders. AIDS-related lymphomas may evolve from an initial multiclonal B-cell expansion similar to that described in other severely immunosuppressed patients (eg, with posttransplantation lymphoma).