T and NK Cell Neoplasms Flashcards
LyP clinical
- 12% cutaneous lymphomas
- chronic, recurrent, self-healing skin dz affecting trunk, extremities, butt
- papular/nodular lesions, centrally necrotic, up to 2cm in diameter
- appear in clusters, recur in same region of body
- regress spontaneously within 4-6 weeks, leaving a hyper-/hypo- pigmented scar
- may get regional LAD
- 20% of patients the dz is preceded by, associated with, or followed by another lymphoma: MF, C-ALCL, cHL
LyP Morphology
- early lesions show mainly perivascular/superficial dermal atypical lymphoid cells surrounded by variale #inflammatory cells
- PMNs within blood vessel lumens nearly a constant feature**
T LBL immunophenotype
CD7 most sensitive Tdt CD3 may be cytoplasmic only - specific CD4/CD8 often coexpressed CD1a, CD2, CD5, CD7, CD10, myeloid antigens variable
Pitfall: CD79a positivity on IPOX
T LBL genetics
Rearrangement T cell receptor loci (alpha/delta, beta, gamma), also IgH frequently
Partners:
Transcription factors: HOX11, HOX11L2, MYC, TAL1, RBTN1, RBTN2, LYL1
Tyrosine kinase: LCK
del(9p) (CDKN2A)
Notch1 mutation
T PLL immunophenotype
Immunophenotype CD2, CD3, CD7 positive Tdt and CD1a negative CD4+/CD8-, CD4+/CD8+ or CD4-/CD8+ Immunohistochemistry TCL1
T PLL genetics
Genetics Clonal TCR rearrangement Inv14 or t(14;14) TCR with TCL1a, TCL1b others
T-LGL immunophenotype
Immunophenotype
CD3, TCR-a/b, CD7, CD8 positive
CD4-
CD11b, CD57, CD56 variable
T-LGL genetics
Genetics
Clonal TCR rearrangement
STAT3 mutations in 40% of cases (NEJM 366:1905, 2012)
CLPD-NK
Morphology
Similar to T-LGL Immunophenotype
CD2, CD3 (cytoplasmic), CD7, CD16, CD56, CD57
Surface CD3-negative
Genetics
Germline TCR
Aggressive NK Cell Leukemia
Morphology Variable, ranging from LGL-like to blastic large cells Immunophenotype CD2, CD3 (cytoplasmic), CD16, CD56 Surface CD3 negative EBV+
Genetics
Germline TCR
EBV+ LPD of Childhood
Systemic EBV+ T cell LPD of childhood:
- Chronic active EBV infection
- Prominent hemophagocytosis
- EBV+
Hydroa vacciniforme-like lymphoma:
-Cutaneous manifestation of T cell, rarely NK cell lymphoma associated with EBV infection
ATLL Clinical
- Endemic in Japan, Caribbean basin, Central Africa
- Caused by human retrovirus, human T-cell leukemia virus type 1 (HTLV-1) – serology testing
- Clinical variants: Acute Lymphomatous, Chronic Smoldering, Hodgkin-like
ATLL Morphology and Genetics
Morphology
Very pleomorphic ranging from small cells with irregular nucleoli to large anaplastic cells
Peripheral blood with “flower cells”
Genetics
Clonal TCR rearrangement
Clonal integration HTLV-1
ATLL Immunophenotype
Immunophenotype CD2, CD3, CD5, CD25 + CD7- CD4+, CD8- (most cases) FOXP3+ (Treg)
Extranodal NK/T Cell Lymphoma, Nasal Type- Morphology & Genetics
Morphology
Diffusely infiltrating cells ranging in size from small to large in size.
Angiocentric and angioinvasive pattern may be present.
Necrosis is often present.
Often presents in nasal cavity or nasopharynx
Genetics
Germline TCR
EBV present as closed episomal DNA
Extranodal NK/T Cell Lymphoma, Nasal Type- Immunophenotype
Immunophenotype CD2, CD56 positive CD3, CD4, CD5, CD8, TCR negative Cytotoxic granules positive EBV positive LMP-1 EBER
Enteropathy Associated TCL- Morphology
Type I
Usually presents as multiple ulcerating masses in the jejunum or ileum
Cells invade mucosa and range in size from small to large
Background mixed inflammatory infiltrate
Associated enteropathy in adjacent mucosa
Type II
Usually sporadic
Monomorphic
Enteropathy Associated TCL- Immunophenotype
Type I CD3, CD7, *CD103 positive* CD5, CD4 negative CD8, CD56 variable TCR a/b
Type II CD3, CD7, *CD103 positive* CD5, CD4 negative CD8, CD56 TCR g/d
Enteropathy Associated TCL- Genetics
Genetics
Clonal TCR rearrangement
HLA-DQA10501, DQB201 genotype
Hepatosplenic TCL- Morphology
Sinusoidal infiltrate of lymphoid cells involving bone marrow, liver, spleen
Cells intermediate in size/scanty cytoplasm
Nuclei oval to irregular with condensed chromatin and +/- small nucleoli
Hepatosplenic TCL- Immunophenotype
CD3, CD7, TIA-1, TCR-g/d positive
CD4, CD8, CD5 negative
Perforin and granzyme B usually negative (even though TIA-1 positive)
Hepatosplenic TCL- Genetics
Isochromosome 7q
Clonal TCR
Subcutaneous panniculitis like TCL- Morphology and Genetics
Morphology
Subcutaneous diffuse infiltrate
Epidermis and dermis typically spared
Cells rim fat cells
Cells small to large with moderate amount of cytoplasm
Nuclei oval to irregular with inconspicuous nucleoli
Genetics
Clonal TCR
Subcutaneous panniculitis like TCL- Immunophenotype
CD3, CD8, TIA-1 positive
CD56-/+
TCR-a/b
EBV negative
MF Morphology and Genetics
Epidermotropic infiltrate of small to intermediate size lymphs
Cells scanty cytoplasms, cerebriform nuclear contours and condensed chromatin
Pautrier microabscesses are characteristic
May involve lymph node ranging from small clusters atypical cells to effacement of architecture
TCR
MF Variants
Pagetoid reticulosis
Folliculotropic MF
Granulomatous slack skin
MF Immunophenotype
CD2, CD3, CD4 (most) or CD8 (rare), CD5 positive
CD7 negative
MF Staging
Stage I: limited to skin; no LN involvement
Stage II: N1-N2 LN involvement or tumors
Stage III: erythroderma, no or N1-N2 LN involvement, low
circulating SS cells
Stage IV: high circulating SS cells or N3 LN involvement
Sezary Syndrome
Erythroderma + LAD + Circulating SS cells
SS cell count:
>1000/uL
CD4:CD8 >10:1
loss of CD7, CD26 or other T cell antigens
Primary Cutaneous CD30+ T LPD
Primary cutaneous anaplastic large cell lymphoma (C-ALCL) Lymphomatoid papulosis (LyP)
Primary C-ALCL Morphology
Diffuse infiltrate typically involving dermis and subcutaneous tissue, similar to systemic ALCL
Primary C-ALCL Immunophenotype
CD4, CD30 positive
CD2, CD3, CD5 variable
EMA, ALK-1 negative
Primary C-ALCL Genetics
Clonal TCR
No t(2;5) or other translocations involving ALK
May have IRF4/DUSP22 translocation
LyP Clinical
Crops of spontaneously resolving papules
LyP Mophology
Wedge shaped polymorphic dermal infiltrate with mixture of atypical lymphocytes and acute and chronic inflammatory cells
May have RS-like cells (Type A lesion) or MF-like (Type B lesion) or ALCL-like (Type C) morphology
LyP Immunophenotype
Atypical T cell phenotype, CD4 positive
Pan-T-cell markers variably expressed
CD30 positive cells in type A/C lesions
LyP Genetics
Clonal TCR rearrangement in approximately 1/2 of cases
Primary Cutaneous TCL, Rare Subtypes
Primary cutaneous gamma/delta TCL
Primary cutaneous CD8 positive aggressive epidermotropic cytotoxic TCL
Primary cutaneous CD4 positive small/medium TCL
Primary Cutaneous Gamma/Delta TCL Morphology and Genetics
Epidermis, dermis, and subcutis may all be involved
Cells rim fat cells if involving subcutis
Cells are small to large with moderate amount of cytoplasm
Nuclei oval to irregular; +/- conspicuous nucleoli
Clonal TCR
Primary Cutaneous Gamma/Delta TCL Immunophenotype
CD3+,CD4-CD8+ or CD3+,CD4+,CD8-, TIA-1+ CD5 negative CD56 -/+ TCR-g/d EBV negative
PTCL, NOS Morphology
Diffuse infiltrate of cells- often a mixture of small, intermediate and large cells with varying proportions
Variants:
T zone variant
Follicular variant
Lymphoepithelioid cell variant (Lennert lymphoma)
PTCL, NOS Morphology
CD4 positive
Variable expression of CD2, CD3, CD5, CD7
Usually lack cytotoxic granule associated proteins
PTCL, NOS Genetics
Follicular variant with t(5;9)(q33;q22) involving ITK and SYK genes
Clonal TCR
AITL Morphology
Partially or completely effaced lymph node with regressed lymphoid follicles
Infiltrating cells are polymorphous small to intermediate sized cells including clear cell immunoblasts
Admixed inflammatory cells in background and increased follicular dendritic cells
Arborizing high endothelial venules are increased
AITL Immunophenotype
CD3, CD4 positive
T follicular helper markers frequently positive:
CD10, BCL6, PD1 (CD279), SAP (SH2D1A), IL21, ICOS, CXCR5, and CXCL13
Increased CD21 positive dendritic cells
AITL Genetics
Frequent TET2 mutations
EBV sequences may be detected
Clonal TCR
ALCL, ALK + Morphology
Large pleomorphic cells with abundant cytoplasm and horseshoe/kidney shaped nuclei (Hallmark cells); involve LN in sinusoidal pattern
Variants:
1) Common variant (70%)- majority of cells Hallmark cells
2) Lymphohistiocytic variant (10%)- large number of admixed histiocytes
3) Small cell variant (5-10%)- small to medium sized cells, Hallmark cells present
ALCL, ALK + Immunophenotype
CD30, ALK1, EMA, clusterin, cytotoxic associated antigens (TIA-1, perforin, granzyme B) positive
Pan-T cell antigens show variable expression, most commonly CD43, CD2, and CD4 positive
ALCL, ALK + Genetics
t(2;5) NPM-ALK or variants
Clonal TCR
ALCL, ALK – Morphology
Large pleomorphic cells similar to those in ALCL, ALK +
ALCL, ALK – Immunophenotype
CD30, EMA, cytotoxic associated antigens (TIA-1, perforin, granzyme B) positive
Pan-T cell antigens show variable expression, most commonly CD43, CD2, and CD4 positive
ALK negative
Rarely PAX5 positive due to gene amplification