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Flashcards in Lymph Nodes Deck (343)
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210

Lymphoblastic lymphoma of T-cell lineage: Most commonly expressed markers (8).

TdT, CD2, CD3, CD5, CD7; CD1a, CD99, CD43.

211

Lymphoblastic lymphoma of T-cell lineage: Less commonly expressed markers (2).

CD10 in 40% of cases.

CD34 in 20% of cases.

212

Lymphoblastic lymphoma of T-cell lineage: Expression of CD4 and CD8.

Most cases are double positive.

A smaller proportion are double negative.

Rare cases express only one of these markers.

213

Lymphoblastic lymphoma of B-cell lineage: Immunophenotype (5,2).

Positive: TdT, CD34, CD10, Pax-5, CD79a.

Negative: CD20, light chains.

214

Lymphoblastic lymphoma: Aberrantly expressed antigens.

Some tumors express myeloid markers such as CD13, CD33, CD117.

215

Lymphoblastic lymphoma: PCR.

T-LBL: Rearrangement of TCR-gamma.

B-LBL: Monoclonal IGH.

Some tumors show both mutations.

216

Lymphoblastic lymphoma: Sanger sequencing.

About half of cases of T-LBL show activating mutations of the NOTCH1 gene.

217

Lymphoblastic lymphoma vs. Burkitt's lymphoma: Immunophenotype.

Burkitt's lymphoma . . .

- Positive: CD20 (bright).
- Negative: CD34, TdT.

218

Lymphoblastic lymphoma vs. T-cell-rich thymoma: Histology (

T-cell-rich thymoma:

- Fibrous bands impart lobular architecture.
- Immunohistochemistry demonstrates epithelial cells.

219

Lymphoblastic lymphoma vs. T-cell-rich thymoma: Flow cytometry.

T-cell-rich thymoma may show various populations of T lymphocytes.

220

Lymphocytic markers that may be expressed by myeloid sarcoma (6).

TdT.

CD4, CD7, CD43.

Pax-5, CD79a.

221

Indolent T-lymphoblastic proliferation: Definition (2).

Polyclonal proliferation of T lymphoblasts.

No change in nodal architecture.

222

Indolent T-lymphoblastic proliferation: Associations (3).

Castleman's disease.

Various hematologic malignancies.

Carcinomas.

223

Indolent T-lymphoblastic proliferation: Treatment.

None required.

224

Lymphoblastic leukemia: Recommended blast count.

More than 25%.

225

Burkitt's lymphoma: Clinical forms.

Endemic.

Sporadic.

Immunodeficiency-associated.

226

Burkitt's lymphoma, endemic:

A. Geography.
B. Median age of patient.
C. Sites.

A. Equatorial Africa.

B. Six years.

C. Abdominal cavity, jaw.

227

Burkitt's lymphoma, sporadic:

A. Median age (2).
B. Sites (2).
C. Lymphadenopathy.

A. Eleven years in children, 30 in adults.

B. Gastrointestinal tract, genitourinary organs.

C. Localized.

228

Burkitt's lymphoma, immunodeficiency-associated:

A. Typical patient.
B. Sites (3).
C. Effect of HAART.

A. One with HIV and a relatively high CD4 count and no opportunistic infections.

B. Lymph nodes, bone marrow, CNS.

C. No effect on incidence of Burkitt's lymphoma.

229

Burkitt's lymphoma: Prognosis.

Can be cured by means of extensive chemotherapy.

230

Burkitt's lymphoma: Immunophenotype (3,3).

Positive: B-cell antigens, CD10, Bcl-6.

Negative: Bcl-2, TdT, Mum1.

231

Burkitt's lymphoma: Relation to EBV.

ISH for EBV . . .

- Endemic: Positive in nearly all cases.
- Other types: Positive in many cases.

232

Burkitt's lymphoma: Cytogenetics.

Rearrangement of 8q24 involving MYC.

233

Burkitt's lymphoma: Clinical predictors of worse prognosis (3).

Older age.

Black race.

Advanced stage of disease.

234

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma: Typical patient.

Older adult with generalized lymphadenopathy or with extranodal disease.

235

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma: Behavior.

Very aggressive:

- Presents in advanced stage.
- Virtually no response to chemotherapy.
- Poor prognosis.

236

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma: Histology (

Often show the starry-sky pattern.

In some tumors, cells are larger or more pleomorphic than those of Burkitt's lymphoma.

In some tumors, the cells resemble those of Burkitt's lymphoma but have a different karyotype.

237

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma: Immunophenotype.

Cases that resemble DLBCL:
- Typical phenotype of Burkitt's lymphoma.
- Proliferation rate of more than 90%.

Cases that resemble Burkitt's lymphoma:
- Strong expression of Bcl-2, or
- Proliferation rate of less than 90%.

238

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma: Mutations.

Cases that resemble DLBCL but have the immunophenotype of Burkitt's lymphoma: Simple rearrangement of MYC.

Cases that resemble Burkitt's lymphoma may have a complex karyotype or a rearrangement of MYC + rearrangement of BCL2 and/or BCL6.

239

B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt's lymphoma:

A. "Double-hit" type.
B. "Triple-hit" type.

A. Rearrangement of (MYC) and (BCL2 or BCL6).

B. Rearrangement of all 3 genes.