AIDS-related plasmablastic lymphomas of the oral cavity and jaws: a diagnostic dilemma.

Acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas are highly pleomorphic in their clinical, pathological, and biological features. Recent investigations have led to the identification of a particular type of AIDS-related non-Hodgkin's lymphomas presenting in the oral cavity and jaws. This novel category of AIDS-related non-Hodgkin's lymphomas derives from B-cells and has been defined as plasmablastic lymphoma on the basis of its morphological and immunophenotypic features. Clinically, AIDS-related plasmablastic lymphoma is generally limited to the oral cavity at the time of diagnosis, although extension to distant sites frequently occurs at a later stage. Histologically, AIDS-related plasmablastic lymphoma is composed of a monomorphic and cohesive pattern of plasmablasts with basophilic cytoplasm. Phenotypically, AIDS-related plasmablastic lymphoma fails to express the most common B-cell-associated surface antigens, whereas it consistently expresses high levels of plasma cell-associated markers, including VS38c and CD138/syndecan-1. For the purpose of differential diagnosis, the morphological and immunophenotypic peculiarities of AIDS-related plasmablastic lymphoma clearly distinguish these lymphomas from other categories of AIDS-related non-Hodgkin's lymphomas, as well as from undifferentiated large cell carcinomas.