Heme Malignancies: T and NK Cell

Question 1

B-cell malignancies are less aggressive when derived from more-differentiated cells. Does this concept apply to T-cells as well?

Answer 1

Nope.

Question 2

What is the immunophenotype of a gamma delta T-cell?

Answer 2

CD3+ surface

CD4/CD8 -

CD7 -

Question 3

What is the immunophenotype of an NK cell?

Answer 3

Cytoplasmic CD3+

Question 4

There are RARELY translocations of oncogenes to TCR promotors, so how do you demonstrate clonality of a T-cell?

Answer 4

PCR-Based Studies of the TCR gene.

Question 5

AITL stands for what?

Where is it predominately found?

Answer 5

Angioimmuniblastic T-cell Lymphoma

Lymphoma = lymph nodes

Question 6

Mycosis Fungoides is primarily found on what part of the body?

Answer 6

Skin

Question 7

What is the subset of Micosis Fungoides that has not only skin presentations, but also peripheral blood involvement?

Answer 7

Sezary Syndrome

Question 8

What is the affected cell type in Angioimmunoblastic T-cell Lymphoma?

Answer 8

CD4 follicular T-cell

Follicular Helper T’s

Question 9

What is the key diagnostic/immunophenotypic feature of AITL?

Answer 9

(Angioimmunoblastic T-cell Lymphoma)

CD10+ Follicular T-cells

That shit ain’t right. CD10 is a germinal center B-cell marker. When expressed BETWEEN follicles, it’s on T-cells, and indicative of cancer.

Question 10

What is the immunophenotype of Follicular Helper T’s in Angioimmunoblastic T-cell Lymphoma?

Answer 10

CD3+
CD4+
CD10+

Question 11

What does the lymph node look like when a patient has AITL?

Answer 11

The paracortex is significantly expanded, and has a lot of new blood vessels.

“Angio” = new blood vessels

KEY`

Question 12

If you immunostain for CD21, what cell are you staining for?

Answer 12

Follicular Dendritic Cells

Question 13

What is the point of staining for follicular dendritic cells?

Answer 13

In Angioimmunoblastic T-cell Lymphoma, there are not germinal centers clearly defined, but the ghosts of the follicular dendritic cells remain. Stain them with immunostain for CD21 (the FDC marker) and see them throughout the entire lymph node.

This is key to the diagnosis of AITL.

Question 14

What is the genetic pattern for Angioimmunoblastic T-cell Lymphoma?

Answer 14

There is not a clearly defined correlation between any specific genetic change and AILT.

Question 15

Describe Peripheral T-Cell Lymphoma NOS (Not otherwise specified).

Answer 15

Anywhere other than the bloodstream

Aggressive

Lymphadenopathy/paraneoplastic syndromes/B symptoms (night sweats fever weight loss)

Question 16

Describe the lymph node morphology of a person with Peripheral T-cell Lymphoma NOS.

Answer 16

Expanded paracortex
Effacement
Distinct subsets of atypical cells.

(Too much uniformity for the lymph node. Generally haphazard arrangement of all kinds of cells)

Paracortical Epithelioid Histiocytes