Chapter 7-Mature T-Cell and NK-Cell Neoplasms
Classes of T Cells
n
αβ T cells
n
Two major subtypes: CD4+ (helper) and CD8+ (cytotoxic) T
cells
n
CD4+ T cells are mainly cytokine-secreting cells
o
Th1 cells secrete Il-2 and interferon γ and provide help
mainly to other T cells and macrophages
o
Th2 cells secrete Il-4, 5, 6 and 10 and provide help to B
cells in their production of antibodies
n
γδ T cells
n
Negative for both CD4 and CD8
n
Comprise <5% of normal T cells and found mainly in the
splenic red pulp, intestinal epithelium, and other epithelial sites.
T-Cell and NK-Cell
Leukemia/Lymphoma
n
Much less common than B cell lymphomas
n
Significant variations in incidence in different geographical
regions and racial populations
n
More common in Asia
n
HTLV-1 main risk factor in Japan and Caribbean
n
Only about 11-12% of lymphomas overall (not including areas
endemic for HTLV-1)
n
T-Cell and NK-Cell Leukemia/Lymphoma
n
Clinical features are very
important in the diagnosis and classification of T and NK cell malignancies.
n
No convenient immunophenotypic marker of clonality
n
No specific antigenic profiles associated with most T cell
lymphoma subtypes
n
Antigen expression may not be specific (e.g., CD30 which is
seen universally in T cell anaplastic large cell lymphoma, but may also be seen
in other T cell lymphomas, some B cell lymphomas, and Hodgkin lymphoma)
n
Many of the clinical manifestations of T cell lymphomas can
be related to cytokine expression by the neoplastic cells.
n
Hypercalcemia associated with Adult T Cell Leukemia/Lymphoma
(ATLL) has been linked to secretion of factors with osteoclast-activation
activity
n
Hemophagocytic syndrome seen in T cell and NK cell
malignancies has been associated with secretion of cytokines and chemokines.
n
NK cells and cytotoxic T cells
express cytotoxic proteins:
Perforin
Granzyme B
T-cell intracellular antigen (TIA-1)
NK cells
n
Share some functions with
cytotoxic T cells
n
Share some markers with
cytotoxic T cells:
n
CD2, CD7, CD8, CD56 and CD57
positive
n
Often positive for the epsilon
chain of CD3
n
Also usually positive for CD16
Types
of mature T-Cell and NK cell neoplasms
n
Leukemic/disseminated
T-cell prolymphocytic leukemia
T-cell large granular lymphocytic
leukemia
Adult T-cell leukemia/lymphoma
n Nodal
Peripheral T-cell lymphoma,
unspecified
Angioimmunoblastic T-cell lymphoma
Anaplastic large cell lymphoma
n
Extranodal
Cutaneous
Mycosis fungoides/Sezary
syndrome
Primary cutaneous CD30+ lymphoproliferative
disorders, including
: Primary cutaneous
anaplastic large cell lymphoma (C-ALCL)
Lymphomatoid papulosis
Borderline lesions
Subcutaneous panniculitis-like T-cell lymphoma
Non-cutaneous
Intestinal/Enteropathy-type
T-cell lymphoma
Hepatosplenic T-cell lymphoma
Nasal type NK/T cell lymphoma
T-Cell Prolymphocytic Leukemia
n
Relatively rare; ~2% of cases of SLL in adults >30 years
n
Leukemic cells in the blood, bone marrow, lymph nodes,
spleen, liver, skin
n
Hepatosplenomegaly, generalized lymphadenopathy, skin
infiltration in 20%
n
Very high lymphocyte count, usually >100 x 109/L;
anemia and thrombocytopenia
n
Serology for HTLV-1 negative
n
Progressive clinical course; <1 year survival
n
Small to medium-sized lymphoid cells
n
Non-granular basophilic cytoplasm
n
Round, oval or markedly irregular nuclei and a visible
nucleolus
n
May have cytoplasmic protrusions or blebs
n
Nuclear outline may be very irregular, raising the
possibility of ATLL (ruled out by HTLV-1 negativity) or Sezary syndrome (ruled
out by clinical history and skin biopsy)
n
Bone marrow diffusely infiltrated
n
If skin is involved, there are dense dermal infiltrates,
often around appendages, but without epidermotropism
n
Immunophenotype
Mature T cell: CD2+, CD3+, CD7+
Negative for TdT and CD1a
60% CD4+, CD8-
25% CD4+, CD8+
15% CD4-, CD8+
n
Cytogenetics: 80%
with inversion of chromosome 14
T-Cell Large Granular Lymphocytic Leukemia
n
Uncommon: 2-3% of cases of small lymphocytic leukemia
n
Involves peripheral blood, bone marrow, liver and spleen;
usually not lymph nodes.
n
Most cases are indolent
n
Severe neutropenia, with or without anemia. May have red cell
hypoplasia due to cytokine production.
n
Lymphocytosis usually not marked, 2,000-20,000.
n
Moderate splenomegaly is the main physical finding.
n
Rheumatoid arthritis, autoantibodies, circulating immune
complexes and hypergammaglobulinemia are also common.
n
Large granular lymphocytes with abundant cytoplasm and fine
or coarse azurophilic granules
n
Granules contain proteins involved in cytolysis such as
perforin and granzyme B
n
Bone marrow involvement is variable
n
Can be divided into groups based on the predominant cell
markers:
n
Common variant (80% of cases)
o
CD3+, TCRαβ+, CD4-, CD8+
n
Rare variants
o
CD3+, TCRαβ+, CD4+, CD8-
o
CD3+, TCRαβ+, CD4+, and CD8+
o
CD3+, TCRγδ+
n
CD11b, CD56 and CD57 are variably expressed; CD57 is often
expressed in the common type
n
TIA-1 is usually positive
n
Prognosis
May be indolent and nonprogressive,
raising the possibility of a reactive
lymphocytosis which may be clonal
in some circumstances.
Morbidity is associated with neutropenia,
but usually not mortality
May progress to a more aggressive disease
with transformation to a PTCL of large
cells
Aggressive N-K Cell Leukemia
·
A systemic proliferation of NK cells
·
Aggressive clinical course
·
Epidemiology
o Rare
o More
prevalent among Asians than Whites
o Mostly
teenagers and young adults
o Slight
male predominance
·
Sites of Involvement
o Most
common
§
PB, BM, liver and spleen
·
Clinical Features
o Usually
present with fever, constitutional symptoms, and a leukemic blood picture
o Number
of circulating leukemic cells low or high (a few % to >80% of all
leukocytes)
o Anemia,
neutropenia, thrombocytopenia common
o Hepatosplenomegaly
common, LAD sometimes
o Skin
lesions uncommon
o Dx
may be complicated y coagulopathy, HPS, or MOF (serum Fas ligand often markedly
elevated)
·
Etiology
o Little
known
o Strong
association with EBV
·
Morphology
o Slightly
larger than normal LGL
o Some
contain irregular, hyperchromatic nuclei
o Nucleoli
inconspicuous or distinct
o Ample
amount of pale or lightly basophilic cytoplasm containing fine or course
azurophilic granules
o BM
shows massive, focal, or subtle infiltration with reactive histiocytes with
hemophagocytosis
o In
tissue sections, often monotonous, with round or irregular nuclei, condensed
chromatin and small nucleoli; frequent admixed apoptotic bodies; necrosis
common
·
Immunophenotype
o CD2+,
surface CD3-, CD3ε+, CD56+, and positive for cytotoxic molecules
o CD11b
and CD16 may be expressed; CD57 usually negative
·
Prognosis and predictive factors
o Most
cases result in fatal outcome in 1 to 2 yrs
o Many
pts die within days to weeks of initial presentation
Adult T-Cell Leukemia/Lymphoma
n
Endemic in several regions: Japan, Caribbean basin, parts of
Central Africa
n
Sporadic in US and elsewhere
n
Caused by HTLV-1
n
Long latency; exposure to virus early in life
n
Adults; median age 55 years; male to female ratio 1.5:1
n
Widespread lymph node involvement
n
Peripheral blood involvement
n
Skin common site (>50%)
n
Systemic with involvement of spleen, skin, lung, liver, GI
tract, CNS
n
Clinical Variants: Acute, Lymphomatous, Chronic, Smoldering
Acute variant
n
Systemic illness with constitutional symptoms
n
Leukemic phase with very high WBC count
n
Skin rash
n
Generalized lymphadenopathy and hepatosplenomegaly
n
Hypercalcemia with or without lytic bone lesions
n
May have immunodeficiency with infections
n
In addition to acute variant, other clinical variants include:
Lymphomatous variant
n
Prominent lymphadenopathy without PB involvement
n
Advanced stage
n
Hypercalcemia less often seen
Chronic variant
n
Skin lesions, most commonly exfoliative rash
n
Fewer atypical lymphocytes in PB
n
No hypercalcemia
Smoldering variant
n
WBC count normal with few atypical cells
n
Skin or pulmonary lesions, but no hypercalcemia
n
Long progression to acute disease in 25% of cases
Morphology
n
Medium-sized to large cells with pronounced nuclear
pleomorphism (polylobated “flower” cells)
n
Patchy marrow infiltrates
n
Osteoclastic activity may be prominent
n
Skin: epidermal infiltrate with Pautrier-like microabscesses
Immunophenotype
·
Express T-cell antigens: CD2, CD3, CD5
·
Usually lack CD7
·
Most cases: CD4-, CD8+, or double positive for
CD4 and CD8
·
CD25 expressed nearly all cases
·
Large transformed cells may be positive for
CD30, but ALK-
·
TIA-1 and granzyme B negative
Prognostic factors:
n
Clinical subtype
n
Age
n
Performance status
n
Serum calcium
n
LDH level
Survival:
n
Acute and lymphomatous: two weeks to one year
n
Chronic and smoldering: longer survival
Peripheral T-Cell Lymphoma, unspecified
n
T-cell lymphomas that don’t meet the criteria for the more
specific types
n
About 50% of the T-cell lymphomas
n
Mostly adults, but may occur in children
n
Usually nodal, but may be extranodal
n
Usually high stage at diagnosis
n
Patients present with lymphadenopathy
n
Constitutional symptoms often present
n
Paraneoplastic features: eosinophilia, pruritus,
hemophagocytic syndrome
n
Aggressive clinical course
n
Patients respond poorly to treatment
n
Relapses are frequent
n
Overall 5 year survival 20-30%
n
Diffuse infiltration with effacement of lymph node
architecture
n
Broad cytologic spectrum: usually predominance of
medium-sized or large cells with irregular nuclei
n
Clear cells and Reed-Sternberg-like cells
n
High endothelial venules increased
n
Polymorphous inflammatory background
n
T-zone variant
n
Interfollicular growth pattern with preserved or even
hyperplastic follicles
n
Tumor cells predominantly small or medium-sized without
nuclear pleomorphism
n
Lymphoepithelial variant (Lennert lymphoma)
n
Diffuse or interfollicular
n
Numerous small clusters of epitheliod histiocytes
n
Immunophenotype
n
T-cell associated antigens (CD3, CD5, CD7)
n
Often show loss of normal antigen expression
n
Most nodal cases are CD4+, CD8-
n
CD30 may be positive, but not cytotoxic granule associated
proteins
n
Some cases may express CD56, usually extranodal with
cytotoxic T-cell phenotype
Genetics: TCR genes clonally
rearranged in most cases
Angioimmunoblastic T-Cell Lymphoma
n
Peripheral T-cell lymphoma characterized by:
n
systemic disease
n
polyclonal gammopathy
n
polymorphous infiltrate in lymph nodes, with a prominent
proliferation of high endothelial venules and follicular dendritic cells
n
Occurs in middle age and elderly patients
n
15-20% of T cell lymphomas; 1-2% of NHL
n
Generalized lymphadenopathy, hepatosplenomegaly, and frequent
skin rash
n
Bone marrow is commonly involved
n
Other findings: edema, pleural effusion, arthritis, ascites
n
Polyclonal gammopathy, circulating immune complexes, cold
agglutinins, positive rheumatoid factor, anti-smooth muscle antibodies
n
Progressive clinical course; survival <3 years
n
Lymph node architecture partially effaced
n
Paracortex diffusely infiltrated by polymorphous population
of small to medium-sized lymphocytes, clear cells, some T-immunoblasts
n
Minimal cytologic atypia
n
Admixed small reactive lymphocytes, eosinophils, plasma
cells, histiocytes, and increased dendritic cells
n
High endothelial venules numerous
n
Immunophenotype
n
Mature T cells with CD4+ > CD8+ cells
n
CD21+ dendritic cells
n
Polyclonal plasma cells
n
EBV+ B cells may be numerous
n
Genetics: T-cell receptor genes rearranged in 75% of cases
Anaplastic Large Cell Lymphoma
n
T-cell lymphoma composed of large atypical cells with
abundant cytoplasm and pleomorphic nuclei
n
About 3% of adult NHL; 10-30% of childhood NHL
n
CD30 positive
n
Express cytotoxic granule associated proteins
n
Most cases positive for anaplastic large cell lymphoma kinase
(ALK) protein
n
ALK-positive ALCL most frequent in first three decades; male
predominance (M:F 6.5:1)
n
ALK-negative ALCL more common in older patients; M:F 0.9:1
n
Frequently involves lymph nodes and extranodal sites
(skin-21%, bone-17%, soft tissues-17%, lung-11%, liver-8%)
n
Patients present with advanced stage; B symptoms, especially
fever
n
Broad morphologic spectrum but all cases contain “hallmark”
cells – large or small cells with eccentric, horseshoe- or kidney-shaped nuclei
n
Cells may resemble Reed-Sternberg cells
n
May show sinusoidal pattern
n
Common, lymphohistiocytic, and small cell variants recognized
n
Immunophenotype
n
CD30+ on cell membrane and in Golgi region
n
ALK expression in 60-85% of cases; nuclear and/or cytoplasmic
staining (very specific for ALCL)
n
EMA+
n
Usually express one or more T-cell antigens, but antigen loss
may result in “null” phenotype
n
Express cytotoxic associated proteins
n
Genetics
n
90% show clonally rearranged TCR
n
t(2:5) or variants involving the ALK gene
nPrognosis and Predictive Factors
ALK+ have better prognosis
5-year survival 80%
Relapses in 30% of cases
ALK- worse prognosis
5-year survival 40%
Blastic NK-cell Lymphoma
·
Composed of cells with a lymphoblast-like
morphology and evidence of commitment to the NK lineage
·
Epidemiology
o Rare
o All
ages; most pt’s are middle-aged or elderly
·
Sites of Involvement and clinical features
o Tends
to involve multiple sites, with a predilection for skin
o LN,
soft tissue, PB or BM can also be involved
o Rarely,
nasal cavity is the primary site
·
Etiology
o Unknown
o Not
related to EBV
·
Morphology
o Diffuse
monotonous infiltrate of medium-sized cells with fine chromatin, resembling
lymphoblastic or myeloblastic leukemia
o A
single-file pattern of infiltration can be identified in areas
o Uncommon
to find coagulative necrosis and angiocentric infiltrate
o Tumor
cell rosettes resembling Homer-Wright rosettes can be formed
o In
Giemsa touch preps, azurophilic granules may or may not be found
·
Immunophenotype
o Negative
for surface CD3
o Positive
for CD56
o CD4
and CD43 usually expressed
o CD2,
CD7, cCD3ε, and cytotoxic molecules is variable, but usually negative
o Some
cases TdT and/or CD34 positive
o The
dx of blastic NK-cell lymphoma should only be made in the absence of commitment
to the T-cell or myeloid lineages; thus, the neoplastic cells should be
negative for surface CD3, MPO, and CD33, and the dx supported by absence of TCR
rearrangement
·
Prognosis and predictive factors
o Clinical
course is aggressive with a poor response to regimens used for non-Hodgkin
lymphomas
o Partial
responses to “acute leukemia-like” regimens have been seen in rare cases
o Cases
with localized skin lesions have a better prognosis
Mycosis Fungoides / Sezary Syndrome
n
Mature T-cell lymphoma
n
Rare (0.3 per 100,000 annual
incidence)
n
Most common subtype of T-cell
lymphomas that arise primarily in skin
n
Adults/elderly
n
Male:Female = 2:1
n
Presents in the skin with
limited patches and/or plaques, frequently on the trunk
n
Long natural history
n
Usually progress to more
generalized disease and to tumors
n
Rare patients develop
erythroderma and/or Sezary syndrome
n
Epidermotropic infiltration of
small to medium-sized T-cells with cerebriform nuclei
n
Pautrier microabcesses
sometimes seen
n
Epidermal involvement with
single cell exocytosis more common
n
Dermal infiltrate may be
bandlike, patchy or diffuse
n
Grading of lymph node
involvement in MF
n
Category I – dermatopathic
lymphadenopathy, no MF
n
Category II – focal involvement
by MF
n
Category III – complete
replacement by MF
n
Immunophenotype
n
CD2+, CD3+,TCRβ+, CD5+, CD4+, CD8-, CD7-
n
Cytotoxic granule associated
proteins not expressed
n
Genetics
n
T-cell receptor genes clonally
rearranged
n Complex karyotypes may be seen
nMycosis
Fungoides Variants
n
Pagetoid reticulosis
Infiltrates strictly epidermal
Localized
(Woringer-Kolopp disease)
Multiple
(Ketron-Goodman disease)
Localized has excellent prognosis
Often CD30 positive
May be CD8+ or CD4+ or negative for both
n
Mycosis fungoides-associated
follicular mucinosis
Follicular,
rather than epidermal, infiltrate
Mucinous
degeneration of the hair follicles
Preferentially
involves head and neck
Indolent
course
n
Granulomatous slack skin
disease
May
be seen with other types of lymphoma (e.g., Hodgkin) and may be separate entity
Slowly
developing folds of atrophic skin
Preferentially
involves axillae or groin
Granulomatous
infiltrate with atypical T lymphocytes, macrophages, multinucleated giant cells
Elastophagocytosis
nClinical
Course:
Most important factor is clinical stage
Patients with limited disease have nearly
normal survival
Adverse prognostic findings:
Advanced stage
Skin tumors and/or extracutaneous
spread
Age over 60 years
Elevated LDH
Transformation to large cell lymphoma
Primary Cutaneous Anaplastic Large Cell Lymphoma
n
T-cell lymphoma with anaplastic
morphology and CD30 positivity
n
Limited to skin at time of
diagnosis by careful staging
n
Clinically important to
distinguish from secondary skin involvement by other types of lymphoma
n
Represents 25% of primary
cutaneous T-cell lymphomas
n
Predominantly seen in
adults/elderly, rarely in children
n
Male:Female = 1.5-2.0:1
n
Solitary or localized skin
lesions
n
Tumors
n
Nodules
n
Papules (rarely)
n
Multicentric cutaneous disease
in 20%
n
May partially or completely
regress; cutaneous relapses frequent
n
Extracutaneous dissemination in
10%
n
Cytologic features similar to
systemic ALCL
n
Pleomorphic, multinucleated
giant cells and R-S-like cells often more numerous
n
Infiltrates diffuse, involving
upper and deep dermis and subcutaneous tissue
n
Epidermal invasion and
ulceration may be seen, but epidermotropism less common
n
Modest inflammatory background
n
Immunophenotype
n
T-cell antigens, usually CD4+
n
CD30+ in majority of cells
(>75%)
n
Cytotoxic proteins in 70% of
cases
n
Variable loss of CD2, CD5,
and/or CD3
n
Usually negative for ALK and
EMA
n
Genetics
n
TCR genes rearranged clonally
in most
n
t(2;5) not found
nClinical
Course
Favorable for disease limited to skin – 90%
survival rate at 5 years
Presence of extracutaneous disease is
unfavorable indicator
Skin-directed therapy (radiotherapy or
surgery) in limited disease
Multi-agent chemotherapy reserved for cases
with extracutaneous disease
Lymphomatoid Papulosis
n
Chronic, recurrent skin disease
characterized by the appearance of spontaneously regressing (3-6 weeks) papules
and an atypical T-cell infiltrate which can mimic T-cell lymphoma
histologically
n
Usually has a benign course,
but lesions often recur
n
Can be clonal and progresses to
lymphoma in some cases
n
Rare disease
n
Predominantly affects
adults/elderly
n
Male:Female = 1.5:1
n
Limited to skin
n Morphology
Wedge-shaped, dermal infiltrates consisting
of atypical T lymphocytes admixed with
varying proportions of
inflammatory cells (neutrophils, eosinophils, macrophages,
small lymphs)
T cells may resemble MF or RS-like cells
Type A: many RS-like cells and inflammatory
cells
Type B: predominance of cells with
cerebriform nuclei, only a few inflammatory cells
Both types may exist in individual patients
n
Immunophenotype
n
CD4+, CD8-
n
Variable loss of pan-T-cell
antigens
n
CD30 positive in Type A lesions
n
ALK negative
n
Cytotoxic granules usually
expressed
n
Genetics
n
Clonally rearranged TCR genes
in about 50% of patients: most Type B lesions and some Type A lesions
n
t(2;5) absent
n Clinical course: mostly benign course of long
duration (years) with relapsing and
remitting lesions
n
Treatment reserved for patients
with large, numerous and/or scarring skin lesions
n
Low-dose methotrexate and
psoralen/UVA (PUVA)
n
Lymphoma develops in 10-20% of
patients
n
MF
n
C-ALCL
n
Hodgkin lymphoma
n
No known criteria to predict
which patients will progress
Subcutaneous Panniculitis-like T-cell Lymphoma
n
Lymphoma of cytotoxic T cells
which preferentially infiltrates subcutaneous tissue
n
Less than 1% of all non-Hodgkin
lymphomas
n
M:F = 1:1
n
Multiple subcutaneous nodules
of varying size, usually on extremities and trunk
n
May have hemophagocytic
syndrome with pancytopenia, fever, and hepatosplenomegaly
n
Lymphadenopathy usually absent
n
Neoplastic cells infiltrate
diffusely through the subcutaneous tissue without sparing septae
n
Overlying dermis and epidermis
are typically uninvolved (except in gamma delta T-cell cases)
n
Cells vary in size, may rim
around fat cells
n
Necrosis and karyorrhexis are common
n
Immunophenotype
n
Positive for cytotoxic granules
n
Most derived from αβ cells, but 25% are from γδ cells
o
αβ cases are usually CD8+
o
γδ cases are usually CD4-, CD8-, CD56+
nGenetics: TCR genes rearranged
nClinical
Course
Dissemination to lymph nodes and other
organs uncommon, usually late in the clinical
course
Natural history aggressive, but often
responds to combination chemotherapy
Hemophagocytic syndrome is frequent and
usually precipitates downhill course
Intestinal / Enteropathy T-cell Lymphoma
n
Tumor of intraepithelial
T-lymphocytes
n
Usually occurs in the jejunum
or ileum
n
Some patients have (or have
history of) celiac disease
n
Patients present with abdominal
pain, often associated with intestinal perforation
n
NK/T-cell lymphoma, nasal type,
is in differential diagnosis
n Morphology
Usually presents with multiple ulcerating
raised mucosal masses
May also present as one or more ulcers or
as a large exophytic mass
Infiltrates intestinal wall with wide
range of cytomorphology, usually medium-sized to
large monomorphic cells
May show marked pleopmorphism
Inflammatory cells (histiocytes & eos)
n
Immunophenotype
n
CD3+, CD5-, CD7+, CD8-/+, CD4-,
CD103+
n
Positive for cytotoxic proteins
n
Varying number of CD30+ cells
n
Subset of small to medium-sized
cells is usually CD8+ and CD56+
n
Genetics
n
HLA DQA1*0501, DQB1*0201
genotype seen in celiac disease
n
TCR β and γ genes
clonally rearranged
n Clinical Course
Usually poor prognosis, but long term
survivals recorded
Recurrences frequent in the small
intestine
Death usually from abdominal complications
Hepatosplenic T-cell Lymphoma
n
Extranodal and systemic
lymphoma usually of cytotoxic T-cells of the γδ type
n
Marked sinusoidal infiltration
seen in the spleen, liver and bone marrow
n
Patients present with marked
hepatosplenomegaly but no lymphadenopathy
n
Bone marrow nearly always
involved
n More common in immunosuppressed pts
n
Immunophenotype
n
CD3+, CD4-, CD8-, CD5-
n
TCRδ1+, TCRαβ-
n
Positive for cytotoxic protein
TIA-1, usually negative for perforin
n
Minority of cases αβtype, considered a
variant of the more common γδ form
n
Genetics
n
TCR γ gene rearrangement
n
Isochromosome 7q in all cases
studied
n
Sometimes other abnormalities
such as trisomy 8
Extranodal NK/T-cell Lymphoma, Nasal Type
n
Predominantly extranodal
lymphoma with broad morphologic spectrum
n
Nasal cavity most common site,
but may occur anywhere
n
More prevalent in Asia, Mexico
and Central and South America
n
M>F
n
May occur in immunosuppressed
and post-transplant patients
n
Present with nasal obstruction
or epistaxis due to mass lesion or extensive mid-facial destructive lesions
n
Variable presentation outside
nasal cavity, e.g., skin ulceration, intestinal perforation
n
May disseminate rapidly
n
May have associated
hemophagocytic syndrome
n
May overlap with aggressive NK
cell leukemia
n
Mucosal sites show extensive
ulceration
n
Diffuse infiltrate
n
Angiocentric and
angiodestructive pattern common with fibrinoid changes in vessels
n
Coagulative necrosis and
apoptotic bodies
n
Cytologic spectrum broad from
small to large anaplastic cells
n
Immunophenotype
n
CD2+, CD56+, sCD3-, cCD3+
n
Positive for cytotoxic proteins
n
Positive for EBV
n
Other T-cell and NK-cell
antigens negative
n
Genetics: Usually TCR and Ig
genes germline