Primary effusion lymphoma, PEL

Definition

A neoplasm of large B-cells presenting as serous effusions without tumour masses. It is always associated with human herpes virus 8 (HHV-8, Kaposi sarcoma herpes virus, KSHV), usually in association with immunodeficiency secondary to HIV. Although often negative for B-cell antigens, the presence of immunoglobulin gene rearrangements is evidence that in most cases these lymphomas are of B cell derivation.

This may be considered a subtype of DLBCL.The majority of PELs occur exclusively as malignant effusions, but some patients secondarily develop solid tissue masses: others present with a mass and later develop an effusion. KSHV-positive solid lymphomas may be designated as extra-cavitary PELs. There is a case report of a nodal large T-cell lymphoma with HHV-8 infection and concomitent peritoneal effusion containing large lymphoid cells in an HIV-positive man3.

Synonyms

Epidemiology

Most patients are HIV+ homosexual males with a low CD4 count 2.

Clinical features

Usually only one body cavity (pleural, pericardial or peritoneal, rarely subarachnoid2) is involved. Other sites include the gastrointestinal tract, soft tissues and other extranodal sites, but their is usually neither lymphadenopathy nor organomegaly1. Patients may also have Kaposi sarcoma1. There is a rare association with multicentric Castleman disease1.

Histopathology

In cytospin preparations, the cells range from immunoblastic to plasmablastic to anaplastic. Some cells resemble Reed-Sternberg cells. Pleural biopsies show cells embedded within fibrin adherent to the pleural surface, in which specimens the cells appear more uniform.

Immunohistochemistry

 

 

primary effusion lymphomas

 
 

CD3

aberrant expression reported, 1/242

 

CD5

1/242

CD10

0/72

CD15

0/172

CD19

frequently negative, 0/182

CD20

frequently negative, 1/292

CD22

1/222

CD30

positive, 18/232

CD38

frequently positive, 11/162

CD45

positive, 28/292

CD79a

frequently negative, 0/92

CD138

positive, 4/102

cIg

frequently negative

sIg

frequently negative

kappa

0/272

lambda

4/272

bcl-6

0/82

pax5

0/42

NK

0/152

HLA-DR

positive1, 16/202

EMA

frequently positive, 16/202

p53 (>20% of cells positive)

0/82

HHV8

nuclear positivity

KSHV LANA (ORF73)

9/92

vIL6

9/92

ORF59

0/22

KSHV-associated K8.1

2/62

LMP-1

negative

EBER

10/132

 

There may be two phenotypic variants1:

Differential diagnosis

Prognosis

The median survival is less than six months1.

References

World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.

1 Pileri, S.A., Dirnhofer, S., Went, P., Ascani, S., Sabattini, E., Marafioti, T., Tzankov, A., Leoncini, L., Falini, B. and Zinzani, P.L. Diffuse large B-cell lymphoma: one or more entities? Present controversies and possible tools for its subclassification. Histopathology 2002;41:482-509.

2 Chadburn, A., E. Hyjek, et al. (2004). "KSHV-positive solid lymphomas represent an extra-cavitary variant of primary effusion lymphoma." Am J Surg Pathol 28(11): 1401-16.

3 Coupland SE, Charlotte F, Mansour G, et al. HHV-8-associated T-cell lymphoma in a lymph node with concurrent peritoneal effusion in an HIV-positive man. Am J Surg Pathol 2005; 29:647-52

This page last revised 17.7.2005.

©SMUHT/PW Bishop