Primary Effusion Lymphoma in Taiwan Shows Two Distinctive Clinicopathological Subtypes with Rare HIV association

Abstract

Aims

To investigate the clinicopatholoigcal and molecular features of primary effusion lymphoma (PEL) in Taiwan and the association with HIV, HHV8, and EBV.

Methods and results

We retrospectively investigated 26 cases with a median age of 76.5. Only one (4%) patient was infected with HIV. Cytologically, all lymphoma cells revealed typical immunoblastic to plasmablastic morphology. Immunohistochemically, HHV8 was positive in 8 (32%) tumours, negative in 17 (68%) cases. All 23 tested cases examined were of the non-germinal centre B-cell phenotype. MYC protein and EBER were positive in 43% (9/21) and 17% (4/23) cases, respectively. IGH, BCL2, BCL6, and MYC were rearranged in 71%, 11%, 12%, 18% cases, respectively. By univariate analysis, the overall survival (OS) was statistically associated with MYC expression (p= 0.012) and BCL2 rearrangement (p= 0.035), but not with the others. By multivariate analysis, no factor was statistically significant. As compared to the HHV8-negative cases, the HHV8-positive cases were mostly of the plasmablastic immunophenotype expressing CD30 and CD138; and with a less frequent expression of pan B-cell markers.

Conclusions

Apart from the phenotypic difference, our HHV8-positive neoplasms were not distinct from the HHV8-negative group. Literature review of 256 cases including our cases revealed that HHV8-positive cases were more frequently associated with HIV and EBV infection, with rare MYC rearrangement, and a poorer prognosis than HHV8-negative cases. We propose to name the HHV8-positive cases as classical or type I PEL and the HHV8-negative cases as type II PEL, stressing the similarities and the distinctive features between these two groups.

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