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