Primary Effusion Lymphoma (PEL)
Epidemiology:
- HHV-8 (universally
associated)
- Most cases
coinfected with EBV
- Immunodeficiency usually
- Majority in the setting
of HIV
- Young to middle
aged homosexual males
- May occur in
HIV-negative older males in areas with high prevalence of HHV-8 (ex.
Mediterranean)
- Rare even in
setting of HIV
Common Sites:
- Pleural
- Pericardial
- Peritoneal
- GI tract
- Soft Tissue
- Other extranodal
sites
Gross features:
- Typically only one
body cavity involved
- effusions
- absence of
lymphadenopathy or organomegaly
- no pleural mass
lesion (think pyothorax-associated DLBCL)
Morphologic features:
- range of
appearances
- large
immunoblastic or plasmablastic cells
- anaplastic
morphology
- large cells
generally
- some pleomorphism
- large nuclei
- round to irregular
- prominent nucleoli
- cytoplasm deeply
basophilic
- can be very
abundant
- vacuoles in
occasional cells
- perinuclear hopf
maybe
- some cells may
resemble R-S cells
- cells adherent to
pleural surface on biopsy
- often embedded in
fibrin
- occasionally invading
pleura
Immunophenotype:
|
Marker:
|
Sensitivity:
|
Specificity:
|
|
HHV-8
|
|
|
|
EBER
|
Most
|
|
|
LMP-1 (neg)
|
|
|
|
CD45
|
Usually
|
|
|
CD19, CD20, CD79a (neg)
|
Usually
|
|
|
Ig’s (neg)
|
Often
|
|
|
CD30
|
Usually
|
|
|
CD38
|
Usually
|
|
|
CD138
|
Usually
|
|
|
CD3 (neg)
|
Aberrent CD3 expression has
been reported
|
|
Molecular features:
- immunoglobulin
genes rearranged and mutated
- some have aberrant
rearrangement of T-cell receptor genes
- HHV-8 genome
present
- EBV in most cases
(absent in HIV-negative elderly patients)
Other features:
References:
- WHO Tumours
of Haematopoietic and Lymphoid Tissue (2001)