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.
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Lymphoblastic lymphoma of T-cell lineage: Less commonly expressed markers (2).
CD10 in 40% of cases.
CD34 in 20% of cases.
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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.
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Lymphoblastic lymphoma of B-cell lineage: Immunophenotype (5,2).
Positive: TdT, CD34, CD10, Pax-5, CD79a.
Negative: CD20, light chains.
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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.
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Lymphoblastic lymphoma vs. T-cell-rich thymoma: Histology (
T-cell-rich thymoma:
- Fibrous bands impart lobular architecture.
- Immunohistochemistry demonstrates epithelial cells.
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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.
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Indolent T-lymphoblastic proliferation: Associations (3).
Castleman's disease.
Various hematologic malignancies.
Carcinomas.
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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.
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Burkitt's lymphoma, endemic:
A. Geography.
B. Median age of patient.
C. Sites.
A. Equatorial Africa.
B. Six years.
C. Abdominal cavity, jaw.
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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.
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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.
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Burkitt's lymphoma: Prognosis.
Can be cured by means of extensive chemotherapy.
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Burkitt's lymphoma: Immunophenotype (3,3).
Positive: B-cell antigens, CD10, Bcl-6.
Negative: Bcl-2, TdT, Mum1.
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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.
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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.
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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.
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