<prompt> All of the following statements regarding primary effusion lymphoma are true, except:It generally presents in elderly patientsThere is often an association with HHV-8The proliferating cells are NK cellsPatients are commonly HIV positive  <response>: Primary effusion lymphoma is an aggressive B cell lymphoma. The proliferating cells are B cells and not NK cells. All other features mentioned above are associated with primary effusion lymphoma. Ref: Harrisons Principles of Internal Medicine, 16th Edition, Pages 1121-22. 