Primary Cutaneous Peripheral T cell Lymphomas Flashcards
(37 cards)
1
Q
What disease entities are contained
in this category because they are rare ?
A
- Primary cutaneous gamma/delta T cell lymphoma
- Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T cell lymphoma
- Primary cutaneous acral CD8+ T cell lymphoma
- Primary cutaneous CD4+ small/medium T cell LPD
2
Q
What is the definition of
PC G/D T cell lymphoma?
A
- primary to the skin
- mature, activated g/d T cells
- cytotoxic phenotype
IMP: G/D TCR may be seen in MF or Lymphomatoid papulosis so just because the G/D TCR is rearranged doesn’t mean it’s this entity.
3
Q
What is the epidemiology of
PC G/D T cell lymphoma ?
A
- very rare, 1% of cuteneous T cell lymphomas
- most occur in adults
- no sex predilection
4
Q
What is the etiology of
PC G/D T cell lymphoma ?
A
- distribution of the disease reflects normal G/D T cells which are essential in the innate immun response
- it is felt that this disease may arise from chronic antigenic stimulation
5
Q
What is the localization of PC
G/D T cell lymphoma ?
A
- generalized skin lesions with variable clinical morphology (see pictures p. 397)
- primarily affect the extremities
6
Q
What are the clinical features
of PC G/D T cell lymphoma?
A
- clinical presentation is variable with plaque like lesions (epidermotropic lesions) to deep dermal/subQ tumors
- usually on extremities but can be at other sites
- dissemination to mucosal or other areas is frequent with progression
- NO involvement of LN, spleen or bone marrow is usually identifed
- HLH often develops
- particularly with panniculitis like tumors
- B symptoms seen in most adults
7
Q
What are the microscopic findings
of PC G/D T cell lymphoma ?
A
- 3 major patterns:
- epidermotropic
- dermal
- subcutaneous
- Epidermal infiltrate can be mild to marked
- SubQ shows rimming of fat cells
- similar to subcutaneous panniculitis like T cell lymphoma
- BUT this entity also has dermal/and or epidermal involvement
- medium to large in size
- large blastic or anaplastic cells are infrequent
- angioinvasion with apoptosis and necrosis is common
8
Q
What is the immunophenotype of
PC G/D T cell lymphoma?
A
- delta TCR gene positive
- CD3 and CD2+
- CD7 +/- and CD56+
- CD5 -
- strong expression of cytotoxic proteins:
- TIA1, Granzyme B and Perforin
- CD4 and CD8 are both usually negative
- CD8 may be expressed in some cases
9
Q
What is the postulated normal counterpart
of PC G/D T cell lymphoma ?
A
- functionally mature and activated cytotoxic G/D T cells
- of the innate immune system
10
Q
What is the genetic profile
of PC G/D T cell lymphoma ?
A
- TRG and TRD genes are clonally rearranged
- V delta 2, consistent with prevalence of these residing in the skin
- EBV is negative
- STAT5B and rarely STAT3 can have activating mutations
- which makes sense because many cytotoxic T cell malignancies have activation of the JAK/STAT pathway
11
Q
What are the prognostic and predictive
factors for PC G/D T cell lymphoma?
A
- usually resistent to multiagent chemotherapy and radiation
- median survival is 15 months
- poor prognosis
- subcutaneous lesions are particularly bad
12
Q
What is the definition of PC CD8+
aggressive epidermotropic cytotoxic T cell lymphoma ?
A
- provisional entity
- proliferation of CD8+ cytotoxic T cells with marked epidermotropism and epidermal necrosis
- what differentiates this entity from other CD8+ cutaneous T cell lymphomas is:
- clinical presentation
- clinical behavior
- histologic features
13
Q
What is the epidemiology of PC
CD8+ aggressive epidermotropic
cytotoxic T cell lymphoma?
A
- very rare disease ( < 1% of all cutaneous lymphomas)
- occurs mainly in adults
- no known predisposing factors
14
Q
What is the localization of PC CD8+
aggressive epidermotropic cytotoxic T cell lymphoma ?
A
- most patients present with generalized skin lesions
15
Q
What is the clinical presentation of PC CD8+
aggressive epidermotropic cytotoxic T cell
lymphoma?
A
- disseminated, eruptive papules, nodules and/or tumors with central ulceration and necrosis
- rarely it presents as a localized lesion
- IMP:
- these lymphomas can disseminate to other visceral sites:
- lungs, testes, CNS, oral mucosa
- LN are often spared
- these lymphomas can disseminate to other visceral sites:
16
Q
What are the microscopic features of PC, CD8+
aggressive epidermotropic cytotoxic
T cell lymphoma ?
A
- variable morphology
- can have a lichenoid pattern with marked pagetoid epidermotropism and subepidermal edema
- or deeper dermal infiltrates with barely any epidermotropism (more likely seen in the localized variant)
- epidermis shows necrosis, ulceration and blister formation
- destruction of adnexal structures is common
- tumor cells
- small-medium-large
- blastic or pleomorphic nuclei are common
17
Q
What is the immunophenotype of PC
CD8+ aggressive, cytotoxic, epidermotropic
T cell lymphoma ?
A
- CD3+, CD8+, CD4-
- alpha Beta F1 +
- Granzyme B+, Perforin +, TIA1+
- CD45RA+, CD45RO-
- CD2 and CD5-
- CD7 variable expression
- CD30 - in most cases
IMP: difficult clinically and by immunophenotype to differentiate from lymphomatoid papulosis (type D)
18
Q
What is the normal counterpart of
PC CD8+ aggressive epidermotropic
cytotoxic T cell lymphoma ?
A
- a skin-homing, CD8+ cytotoxic T cell
- alpha beta type
19
Q
What is the genetic profile of PC CD8+
aggressive epidermotropic cytotoxic
T cell lymphoma ?
A
- specific genetic abnormalities have not been identified
- No EBV ISH
20
Q
What is the prognosis and predictive factors
for PC CD8+ aggressive epidermotropic
cytotoxic T cell lymphoma ?
A
- aggressive disease with median survival of 12 months
- no difference in clinical outcome between large and small cell morphology and generalized or localized variant
21
Q
What is the definition of PC acral CD8+
T cell lymphoma ?
A
- Rare, cutaneous tumor composed of a skin infiltration of atypical medium-sized cytotoxic lymphocytes
- preferential involvement of acral sites, particularly the ears
- associated with a good prognosis
22
Q
What is the epidemiology of
PC CD8+ acral T cell lymphoma ?
A
- disease of adults
- median age is 53 years
- male predominance is seen
23
Q
What is the etiology of PC
CD8+ acral T cell lymphoma ?
A
- unknown etiology
- an infectious agent is suspected but has not been proven
24
Q
What are the clinical features of
PC CD8+ acral T cell lymphoma?
A
- generally a localized lesion
- reddish papule or nodule
- slow growing over weeks to months
- most frequent sites: ear > nose > foot
- rarely can have multiple lesions or bilateral lesions of the same site
25
What are the microscopic features of
PC CD8+ acral T cell lymphoma ?
* monotonous dermal infiltration of medium sized lymphocytes
* they have irregular, frequently folded nuclei and small nucleoli
* mitoses and apoptoses are rare
* reactive B lymphoid aggregates of follicles may be interspersed with this infiltrate
* other inflammatory cells should be rare or absent (eos, histiocytes, etc)
* epidermis is spared with a grenz zone
* underlying adipose tissue is almost always involved
* skin appendages are always spared
* angiodestruction and necrosis are never seen
26
What is the immunophenotype of PC
CD8+ acral T cell lymphoma ?
* CD3, CD8, TIA-1 and beta F1 are positive
* TIA-1 shows golgi like staining pattern
* CD2, CD5 and CD7 are regularly positive but may be weak or lost
* CD4 always negative
* Granzyme and Perforin are usually negative
* CD56, CD57, CD30, TdT, EBV and TFH cell markers are negative
* CD68
* frequently patchy positive with golgi like pattern of staining
* Ki67
* usually \<10%
* if \>50% consider a different lymphoma
27
What is the postulated normal counterpart of
PC CD8+ acral T cell lymphoma ?
* CD8+ skin homing T cell
* but other locations of have been described including the GI tract
* thought to now be a CD8+ memory T cell
28
What is the genetic profile of PC
CD8+ acral T cell lymphoma ?
* specific genetic alterations have not yet been described
* EBV is negative
29
What are the prognostic and predictive factors
of PC CD8+ acral T cell lymphoma ?
* this lymphoma has a very good prognosis
* complete remission after surgical excision or local radiation
* no evidence of dissemination
* local recurrence may happen
* NO chemotherapy is needed
30
What is the definition of PC
CD4+ LPD ?
* small/medium size cells with pleomorphic morphology
* present with a solitary skin lesion without evidence of plaques or patches of MF
* similar clinical presenation to cutaneous pseudo- T cell lymphoma with a nodular growth pattern
31
What are the epidemiology and localization for
PC CD4+ T cell LPD ?
* rare disease, ~2% of all skin T cell lymphomas
* usually present as a solitary plaque or nodule
* common on the face, neck or upper trunk
32
What are the clinical features of PC
CD4+ T cell LPD ?
* patients are usually asymptomatic
* single slow-growing lesion
* rare cases have multiple lesions
* No clinical evidence of MF should be seen
33
What are the microscopic findings for PC
CD4+ T cell LPD ?
* dense or diffuse or nodular infiltrates within the dermis and a tendency to infiltrate the subcutis
* epidermotropism can be focally present
* IF conspicuous the diagnosis of MF should be considered
* cytology
* predominance of small/medium pleomorphic T cells
* \<30% can be large and pleomorphic
* CD4+ T cells are usually admixed with small, reactive CD8+ T cells, B cells, PC, and histiocytes, including multinucleated giant cells
34
What is the immunophenotype of PC CD4+
T cell LPD ?
* CD3+, CD4+, CD8-, CD30-
* Loss of pan T cell antigens (except for CD7) is uncommon and cytotoxic proteins are not expressed
* atypical T cells express:
* PD1, BCL6 (variable), and CXCL13 suggesting TFH derivation
* CD10 is negative
* Ki67 is usually low 5-20% at most
35
What is the postulated normal counterpart
for PC CD4+ T cell LPD ?
* skin-homing CD4+ T cell with TFH-cell characteristics
36
What is the genetic profile of PC
CD4+ T cell LPD ?
* TCR genes are usually clonally rearranged
* specific genetic abnormalities have not been identified
* EBV is negative
37
What are the prognostic and predictive factors
for PC CD4+ T cell LPD ?
* excellent prognosis
* intralesional steroids, surgical excision or radiotherapy are preferred treatments
* local recurrences are rare
