Body Cavity-Based Lymphoma in a Country with Low Human Immunodeficiency Virus Prevalence: A Series of 17 Cases from the Consortium for Improving Survival of Lymphoma

A Comprehensive Clinicopathologic and Molecular Study of 19 Primary Effusion Lymphomas in HIV-infected Patients

Primary effusion lymphoma (PEL) is associated with human herpesvirus 8 and frequently with Epstein-Barr virus (EBV). We report here a single-center series of 19 human immunodeficiency virus-associated PELs, including 14 EBV+ and 5 EBV- PELs. The objectives were to describe the clinicopathologic features of PELs, with a focus on programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, to search for genetic alterations by targeted deep sequencing analysis, and to compare the features between EBV+ and EBV- cases. All the patients were male, and the median age at diagnosis was 47 years old (interquartile range: 40 to 56 y). Reflecting the terminal B-cell differentiation, immunophenotypic profiles showed low expression levels of B-cell markers, including CD19 (0/19), CD20 (1/19), CD79a (0/19), PAX5 (1/19), BOB1 (3/19), and OCT2 (4/19), contrasting with a common expression of CD38 (10/19), CD138 (7/19), and IRF4/MUM1 (18/19). We observed a frequent aberrant expression of T-cell markers, especially CD3 (10/19), and less frequently CD2 (2/19), CD4 (3/19), CD5 (1/19), and CD8 (0/19). Only 2 cases were PD-L1 positive on tumor cells and none PD-1 positive. With respect to immune cells, 3 samples tested positive for PD-L1 and 5 for PD-1. Our 36-gene lymphopanel revealed 7 distinct variants in 5/10 PELs, with either a single or 2 mutations per sample: B2M (n=2), CD58 (n=1), EP300 (n=1), TNFAIP3 (n=1), ARID1A (n=1), and TP53 (n=1). Finally, we did not observe any major clinical, pathologic, or immunohistochemical differences between EBV+ and EBV- PELs and the outcome was similar (2-y overall survival probability of 61.9% [95% confidence interval, 31.2-82.1] vs. 60.0% [95% confidence interval, 12.6-88.2], respectively, P=0.62).

Human herpesvirus-8-positive primary effusion lymphoma in HIV-negative patients: Single institution case series with a multidisciplinary characterization

BACKGROUND

Primary effusion lymphoma (PEL) is a very rare non-Hodgkin lymphoma caused by human herpesvirus-8 (HHV8) that grows in liquid phase within body cavities. The diagnosis of PEL is based on cytology but requires confirmatory ancillary tests. PEL occurs mainly in association with HIV infection. This study describes 9 cases of PEL in HIV-negative patients and compares their characteristics with 10 HIV-associated cases of PEL diagnosed at a single institution in Italy between 1995 and 2019.

METHODS

Clinical records were reviewed for demographic data, comorbidities, laboratory abnormalities, and outcome. PEL samples were evaluated for cytomorphology, immunophenotype, immunoglobulin (IG)/T cell receptor (TR) rearrangements, and HHV8 and Epstein-Barr virus (EBV) viral loads in effusion supernatants.

RESULTS

HIV-unrelated PEL occurred in 8 elderly patients (7 men, 1 woman) and 1 young adult with primary antibody deficiency. Cytology revealed HHV8-positive lymphoma cells lacking B/T cell antigens and exhibiting 2 cell patterns (polymorphous or monotonous). IG was clonally rearranged in all cases; aberrant TRG occurred in 2 cases. Effusion supernatants had more than 10⁶ HHV8 DNA copies per mL and variable loads of EBV DNA. Compared with HIV-associated PEL, the HIV-negative cohort was characterized by older age, less frequent association with Kaposi sarcoma and/or multicentric Castleman disease, comparable but less abnormal laboratory parameters, and a nonsignificant survival benefit. PEL cases with low apoptosis were associated with better prognosis.

CONCLUSION

To the best of our knowledge, our case series of HIV-unrelated PEL is the largest thus far, expands the spectrum of cytological findings, and supports the need for a multidisciplinary approach in the diagnostic workup.

Clinicopathologic characteristics and survival of patients with primary effusion lymphoma

Primary effusion lymphoma (PEL) is an aggressive B-cell lymphoma confined to body cavities and universally associated with human herpesvirus type 8 infection. The prognosis of this entity remains poor, with a median survival time of 6 to 9 months. To better understand the clinicopathologic features of the disease and identify possible prognostic factors, we performed a systematic review of the literature for cases of PEL, including 2 previously unreported cases from our institution. PEL was more prevalent in men (92%), with a median age at diagnosis of 55 years. The median overall survival for the entire series was 6 months. Peritoneal involvement (HR:1.62; 95% CI:1.06-2.48) and elevated serum lactate dehydrogenase (LDH) levels (HR:2.50; 95% CI:1.21-5.19) were associated with higher risk of death, while pericardial involvement (HR:0.43; 95% CI:0.20-0.94) was associated with lower risk of death. Therefore, effusion site and serum LDH levels are potential prognostic factors in patients with PEL.

Primary effusion lymphoma in human immune deficiency (HIV)-negative non-organ transplant immunocompetent patients

Primary effusion lymphoma (PEL) is a rare non‐Hodgkin's lymphoma most commonly occurring in the context of human immune deficiency (HIV) infection. Herpes virus 8 (HHV‐8) has been associated with PEL and considered to be the etiologic agent. In addition, most cases (60%‐90%) also show evidence of Epstein‐Barr virus (EBV) infection. We describe here an elderly man who was HIV seronegative and immunocompetent, and presented with worsening weakness and ascites. The diagnosis of PEL was rendered cytologically and supported by the results of flow cytometry. The presence of HHV‐8 was demonstrated by immunohistochemistry, whereas EBV‐associated genetic material was absent by EBER ISH. No lymphadenopathy or organ involvement with lymphoma was found. Systemic chemotherapy with lenalidomide was started given the poor prognosis and commodities of severe coronary artery disease; however, the patient did not respond and succumbed to his disease in 4 months. We present detailed cytologic and clinical findings of this very rare occurrence, and review literature of all reported PEL cases of HIV‐negative, nontransplant, immunocompetent patients.