Regression of a plasmablastic lymphoma in a patient with HIV on highly active antiretroviral therapy.

We describe an HIV-infected 44-year-old man who presented 1 month after discontinuation of HAART therapy with a large mass extending from the mediastinum, enclosing the heart and extending through the diaphragm to the epigastric region. Biopsies subsequently revealed a highly aggressive non-Hodgkin's lymphoma (NHL) producing sheets of cells with an organoid distribution. The cells had abundant basophilic cytoplasm and a plasmacytic appearance. Although immunohistochemistry failed to show either B- or T-cell markers, antigens consistent with plasma cells were found. An immunoglobulin heavy chain clonal rearrangement was identified by PCR analysis. These studies were supportive of a diagnosis of a plasmablastic lymphoma. While awaiting the results of these tests, the patient was reinitiated on his HAART regimen. He was found on follow-up a month later to have complete resolution of his bulky mediastinal mass. He remained free of disease for 3 months with subsequent rectal and abdominal recurrence. Treatment with CHOP chemotherapy with filgrastim support was begun which resulted in another remission. Plasmablastic lymphoma is now reported in some studies to account for 2.6% of all HIV-related NHL. Originally described in 1997 in a series of 16 patients, this entity is highly associated with HIV infection in its later stages. Often, patients present with oral or jaw lesions with a rapidly progressive course. The tumors have the morphologic appearance of a plasmacytoid tumor with high proliferative index. Markers are positive mainly for LCA, CD79a, VS38C, and CD138. Co-infection with HHV-8 and EBV has not been consistently reported. Therapy with standard regimens has variable response. One case has been reported with a 3.5 year disease free survival. The regression of disease after resumption of HAART therapy alone in this patient suggests that HAART has an important role in the treatment of lymphoma in the HIV infected patient.