Clinicopathological characteristics compared between primary effusion lymphoma and human herpesvirus 8 (HHV8)-unrelated primary effusion lymphoma-like lymphoma.

Abstract

e19024 Background: Primary effusion lymphoma (PEL) and human herpesvirus 8 (HHV8)-unrelated primary effusion lymphoma-like lymphoma (PEL-LL) are among the most rare subtypes of non-Hodgkin B-cell lymphoma. Although a few number of case reports and small case series have suggested a better outcome of PEL-LL compared to PEL, systematic comparison of prognosis between PEL and PEL-LL has never been conducted owing to their rare incidence. Methods: We consecutively collected PEL and PEL-LL patients diagnosed between 2000 and 2016 in 10 institutions in South Korea. All patients were cytogically confirmed and received systemic evaluation to exclude detectable tumor formation. Clinicopathological characteristics and prognosis were compared. Results: A total of 12 PEL and 4 PEL-LL cases were analyzed. Median age at diagnosis was 68.5 (range, 40-88) and 68.5 (range, 59-77) for PEL and PEL-LL, respectively. Male-to-female ratio was 7:5 and 3:1 in each group. Pleural effusion was the most common presentation in both groups. One patient in PEL-LL group presented with vitreous fluid containing lymphoma cells. Seven and two PEL patients were treated with CHOP and CVP-based chemotherapy, respectively and 3 did not receive chemotherapy due to poor performance. Three PEL-LL patients were treated with R-CHOP and the remaining 1 patient with malignant vitreous fluid received high dose methotrexate. One PEL patient received autologous hematopoietic stem cell transplantation after second remission and lived over 14 years thereafter. With estimated median follow-up duration of 99.6 and 20.7 months for PEL and PEL-LL respectively, 3 and 1 death occurred during the entire period in each group. Median overall survival was 119.6 and 66.5 months in PEL and PEL-LL group respectively without statistically significant difference. Conclusions: In our study, long-term prognosis of PEL and PEL-LL showed no difference. This result might be attributed to 2 remarkably long-lived patients in PEL group (longer than 174 and 123 months, respectively) and low statistical power owing to the small sample size.