EBV-associated primary lymphomas in salivary glands of HIV-infected patients

The lymph nodes within and around salivary glands are commonly involved in inflammatory processes, but rarely the site of primary lymphomas. We observed six cases of primary salivary gland lymphoma in HIV-infected patients and studied them in parallel with three cases of primary salivary gland lymphoma unrelated to HIV and three cases of HIV-related salivary gland lymphadenopathies in order to characterize this new entity. We found that all salivary gland lymphomas in HIV-infected patients were of high histologic grade while salivary gland lymphomas unrelated to HIV were predominantly of low grade MALT type. All lymphomas in both categories expressed the B-cell phenotype. Just as HIV-unrelated lymphomas frequently arise on the background of chronic inflammatory lymphoid processes, lesions characteristic of HIV-lymphadenopathy were still present in some lymphomas of HIV-infected patients. EBV RNA transcripts (EBER) were demonstrated in three, and latent membrane protein (LMP) in two of the six HIV-related and in none of the three HIV-unrelated lymphomas. The three EBER-positive lymphomas were of the histologic types known to express the virus in most cases. The presence of HIV in the form of the core protein p24 and envelope glycoprotein gp41 on the dendritic reticular cells of germinal centers was ascertained in the cases of HIV-related lymphadenopathies but also in the coexistent lymphadenopathies of lymphomas. The practical importance of diagnosing the salivary lymphadenopathies and lymphomas associated with the HIV-infection resides in avoiding their misdiagnosis and surgical removal as tumors of salivary glands.