The cytopathological spectrum of lymphomas in effusions in a tertiary center in Taiwan

Lymphomas presenting in effusions could either be primary or secondary, with very limited data from Taiwan. Methods: We retrospectively reviewed effusion lymphomas from our archives in a tertiary center from July 2011 to June 2019. Results: We identified 59 specimens from 43 patients, including 7 cases with primary effusion lymphoma (PEL) and 36, secondary effusion involvement. Half of the secondary cases presented concurrently with effusion lymphoma, while the remaining half-experienced effusion lymphoma during disease progression. All patients with PELs were males with a median age of 77 and presented with massive pleural effusion. None was HIV-related. Two (29%) PEL cases were positive for human herpes virus 8 (HHV8). The only case with plasmablastic phenotype in the PEL group was positive for both HHV8 and EBV. Four patients died shortly after diagnosis; while the remaining three were alive at the last follow-up (two at 13 months and one at 99 months). Of the secondary cases, diffuse large B-cell lymphoma/high grade B-cell lymphoma was the most common (n = 16, 44%), followed by mantle cell lymphoma (n = 5, 14%). Only 8 cases (22%) were T-cell neoplasms. Prognosis for patients with secondary effusion involvement was dismal, with 1- and 2-year overall survival rates at 17% and 8%, respectively. Conclusion: We found a wide cytopathological spectrum of effusion lymphoma in Taiwan. Most of our PEL cases were distinct from that defined in the World Health Organization scheme by a B-cell phenotype, HHV8-negativity, and absence of immunodeficiency. As compared to PEL cases, the prognosis of those with secondary involvement was extremely poor.