Extranodal NK/T cell Lymphoma, nasal type Flashcards
What is the definition of extranodal
NK/T cell lymphoma, nasal type ?
- most cases appear to be genuine NK cell neoplasms but some cases have been shown to have cytotoxic T cell lineage
- characterized by vascular damage and destruction
- prominent necrosis
- cytotoxic phenotype
- associated with EBV
What is the epidemiology of
this lymphoma ?
- more prevalent in Asians and indigenous populations of south America
- most often seen in adults
- more common in males
What is the etiology of this lymphoma ?
- strong association with EBV
- EBV is present in a clonal episomal form
- type II latency
- EBNA1+, EBNA2-, and LMP1+
- disease activity can be measured with circulating EBV DNA
Note: this lymphoma can occur with immunosuppression
What is the localization of this lymphoma ?
- almost always has an extranodal presentation
- upper aerodigestive tract is most common but other sites can be involved
- skin, soft tissue, GI tract etc
- IMP: rare cases with features of intravascular lymphoma (skin and CNS locations) have been reported
- upper aerodigestive tract is most common but other sites can be involved
Although very rare, primary EBV positive nodal
T cell or NK cell lymphomas have been reported
in what clinical setting?
- primary nodal
- usually in the elderly patients or those with immune deficiency
- monomorphic pattern of infiltration
- lack angiodestruction and necrosis
- which is different from extranodal NK T cell lymphoma
What are the clinical features of this lymphoma ?
- usually obstruction of the upper aerodigestive tract, mass, or extensive midline destruction
- the disease can diseminate to various sites
- HLH can occur due to this lymphoma
- skin lesions are commonly nodular with ulceration, GI tract presents with obstruction or perforation
- genearlly high stage disease at presentation
- systemic symptoms: fever, malaise, and weight loss can be present
What are the microscopic features
of NK/T cell lymphoma ?
- features are similar, irrespective of site of involvement
- diffuse infiltrate of lymphocytes
- fibrinoid changes in the blood vessels and angiodestruction are common
- broad cytological spectrum
- can be small to medium in size or large
- generally is a mixture of cell sizes
- irregular nuclear contours, may seem elongated
- nucleoli are generally inconspicuous
- cytoplasm is moderate in amount, pale
- azurophilic granules can be seen on giemsa stain
IMP: can have a mixed inflammatory infiltrate that can mask the lymphoma…..be careful. Also, pseudoepitheliomatous hyperplasia
What is the most common
immunophenotype of extranodal NK/T cell lymphoma?
- Positive:
- CD2, cCD3, CD56
- CD45Ro and CD43
- CD30 ~30% of cases
- Negative
- CD5, sCD3
- CD4, CD8, CD16, and CD57
- CD7
- variably expressed
- Note, cases with a cytotoxic immunophenotype may be positive for: CD5, CD8 and TCR g/d or a/b. Cytotxic molecules, HLA-DR and CD25
What is the classification is the lymphoma
is cCD3 (epsilon)+, CD56-, cytotoxic
molecules + and EBV+ ?
- extranodal NK/T cell lymphoma
- this is because they have a similar clinical presentation and disease prognosis when compared with the CD56+ subtypes
Note: if the cytotoxic molecules or EBV were - then the classificatio would be a peripheral T cell lymphoma NOS
If EBV is negative then the diagnosis of extranodal NK/T cell lymphoma should be questioned
What is the genetic profile of the
antigen receptor genes ?
- TR and IG are in the germline configuration in most cases
- those that have TR gene rearrangement (10-40%)
- likely to be of the cytotoxi immunophenotype
What cytogenetic aberrations have
been identified in this lymphoma?
- there are many but none are specific to this entity
- review p. 371
What are the key prognostic and predictive
factors for NK/T cell lymphoma ?
- variable prognosis with some patients responding well to therapy and others that do not
- highly aggressive disease with poor overall survival
