Large B cell Lymphomas Part II

Question 1

What is the key clinical history for

Plasmablastic Lymphoma?

Answer 1

• Male predominance
• occurs mostly in HIV
  
  • also seen in post-transplant, autoimmune, and elderly
• can arise in extranodal sites
  
  • mostly oral cavity

Question 2

What is the morphology of

Plasmablastic Lymphoma?

Answer 2

• composed of large B cells with immunoblastic or plasmablastic morphology

Question 3

What are the key IHC

findings for Plasmablastic Lymphoma?

Answer 3

• CD38, CD138 (+)
• IRF4/MUM1 (+)
• cytoplasmic Ig (+)
• EBV (+)
• Negative
  
  • CD45
  • CD20

Question 4

How is Plasmablastic lymphoma differentiated

from Plasmacytoma and Primary Effusion Lymphoma?

Answer 4

• Plasmacytoma
  
  • will be positive for CD56
  • Plasmablastic lymphoma- negative
• Primary Effusion Lymphoma
  
  • positive for HHV8
  • Plasmablastic lymphoma- negative

Question 5

What is the low-power morphology of

Plasmablastic lymphoma?

Answer 5

• starry sky
• diffuse growth without necrosis
• increased apoptosis and mitosis
• deep blue cytoplasm of cells
• absent dutcher or russell bodies

Note: EBV (+) excludes myeloma

* but if B cell markers are positive consider a DLBCL

Question 6

What is a common genetic alteration

in Plasmablastic Lymphoma?

Answer 6

• MYC gene aberrations
• seen in 1/3 of cases

Question 7

What are key things to know

regarding Intravascular Large B cell Lymphoma?

Answer 7

• symptoms are related to small vessel occlusion
• lymph node involvement is rare
  
  • tumor often diagnosed on skin biopsies

Question 8

What is the clinical presentation of

Primary Effusion Lymphoma?

Answer 8

• strongly associated with HHV-8, especially in AIDS patients
• Presents with:
  
  • Effusions (pleural, pericardial, peritoneal)
  • large atypical lymphocytes with immunoblastic, plasmablastic or anaplastic morphology
  • cytoplasmic vacuolization
• Extracviatary PEL
  
  • soft tissue or nodal mass

Question 9

What is the immunohistochemical profile of

Primary Effusion Lymphoma?

Answer 9

• Positive:
  
  • CD45, CD30, CD38, CD138 and EMA
  • HHV8, EBV, and MUM1
• Negative:
  
  • for B and T cell markers and myeloid markers

Question 10

What is the clinical presentation of

Primary Cutaneous DLBCL, leg type?

Answer 10

• affects predominantly elderly women
• 90% of cases on lower extremity
  
  • but can be anywhere

Question 11

What are the morphological findings

of primary cutaneous DLBCL, leg type?

Answer 11

• nonepidermotropic, deep seated
• large B cells, nodules of tumor in dermis
  
  • positive for pan B cell markers
  • BCL2 and BCL6 positive
  • MUM1 +
  • CD10 negative

Note: BCL2 will be negative in Primary cutaneous FL

Question 12

What is the clinical for Lymphomatoid granulomatosis?

Answer 12

• it is an angiocentric, destructive, large B cell lymphoma
• commonly affects lungs
  
  • may involve upper aerodigestive tract, brain, kidneys, and liver
  • IMP: must have lung involvement if there are other foci

Question 13

What is the morphology and IHC of

Lymphomatoid granulomatosis?

Answer 13

• neoplastic cells infiltrating into vessel walls, can look like a vasculitis
• large number of reactive T cells
  
  • plasma cells and histiocytes
• associated with EBV infection and immunodeficiency
• IHC:
  
  • large B cells are EBV
  • CD20 +

Question 14

What is the grading for

Lymphomatoid Granulomatosis?

Answer 14

• Based on EBV positive cells / HPF
• Grade 1: < 5
• Grade 2: 5-20
• Grade 3: > 20

Question 15

What are the key clinical findings

of DLBCL associated with

chronic inflammation?

Answer 15

• B cell lymphoma that arises at sites of longstanding inflammation
• prototype is lymphoma arising within a longstanding pyothorax
• neoplastic cells express EBV

Question 16

What is the key clinical presentation

for EBV + DLBCL, NOS?

Answer 16

• affects extranodal sites of elderly adults in Asian populations
• neoplasm is thought to be related to immune system senesence
  
  • no immune deficiency or piror history of lymphoma
• IHC:
  
  • CD10 and BCL6 are negative
  • MUM1 and EBV are positive

Question 17

What are the EBV + large

B cell neoplasms?

Answer 17

• Plasmablastic lymphoma
• Primary effusion lymphoma
• Lymphomatoid granulomatosis
• DLBCL associated with chronic inflammation
• EBV+ DLBCL, NOS
• EBV + mucocutaneous ulcer
  
  • Hodgkin like features
  • indolent course

Question 18

What are the most common lymphomas

in HIV infection?

Answer 18

• Burkitt lymphoma
• DLBCL
  
  • especially of the CNS
• PEL
• Plasmablastic lymphoma
• Hodgkin Lymphoma

Question 19

What is the key clinical association/features

in PTLD?

Answer 19

• abnormal lymphoid proliferation following transplantation
  
  • usually within the first year
• EBV has been implicated in most cases
  
  • seen in early cases
  • EBV (-) are seen later in the course
    
    • usually > 5 years, more aggressive
• Elevated EBV-DNA viral load is predictive of an emerging PTLD

Question 20

Who is at risk for developing

PTLD?

Answer 20

• Heart-lung, liver-bowel reciepients, highest
  
  • renal and BM, lowest incidence
• children are most at risk
• EBV negative recipient at time of transplant, high risk
• Most immunosuppressed, highest risk

Question 21

What is true of most PTLD origins ?

Answer 21

• most PTLDs are clones of recipient origin
  
  • < 10% are of donor origin
• PTLD often involves the allograft itself
• spectrum of proliferations
  
  • reactive plasmacytosis all the way to monomorphous PTLD
    
    • majority of those are high grade B cell lymphomas

Question 22

What is the morphology of Burkitt Lymphoma?

Answer 22

• diffuse proliferation of intermediate cells
  
  • rim of basophilic cytoplasm
  • round nuclei with multiple nucleoli
• tingible body macrophages impart Starry sky appearance

Question 23

What is the immunophenotype of

Burkitt Lymphoma?

Answer 23

• Positive
  
  • CD19, CD20, CD22
  • CD10, BCL6
  • MYC, ki67 99%
  • surface Ig
• Negative
  
  • BCL2
  • CD5, CD23
  • Tdt, CD34

Question 24

What are the key genetics of Burkitt

Lymphoma?

Answer 24

• positive for MYC gene rearrangement
  
  • MYC/IGH fusion
  • t(8;14)
• also MYC can rearrange with the light chains
  
  • IgK (2p12)
  • IgL (22q11)

Question 25

What is Burkitt-like lymphoma with 11q aberration?

Answer 25

• resembles Burkitt lymphoma
• lacks the MYC gene rearrangement
• shows a chromosome 11q alteration
• clinical course similar to Burkitt lymphoma