Human herpesvirus-8-unrelated primary effusion lymphoma of the elderly not associated with an increased serum lactate dehydrogenase level: A benign sub-group of effusion lymphoma without chemotherapy.

Human herpesvirus-8-unrelated primary effusion lymphoma characterized by lymphomatous effusion without nodal lesions occasionally exhibits spontaneous remission. To elucidate the factors associated with a good prognosis, this study analyzed the clinical parameters of four patients treated in the department and 109 patients reported in case reports. The median age was 71 years and the median overall survival was 20 months. Patients possessing two independent favorable factors, an elderly status (≥ 70 years) and low serum lactate dehydrogenase (< 500 IU/L) showed a markedly higher 1-year survival than patients lacking either of the two factors in the absence of chemotherapy (94% vs 20%, p = 3 × 10(-5)), which was similarly observed in the chemotherapy group (94% vs 51%, p = 0.002). The use of rituximab was also a strong predictor of survival (89% vs 49%, p = 7 × 10(-6)). Elderly patients not exhibiting an increased lactate dehydrogenase may represent a benign sub-group of effusion lymphoma, which do not require chemotherapy to achieve remission.