Haematology Flashcards
What nonreceptor tyrosine kinase is abnormal in chronic myeloid leukaemia. What is the nature of this abnormality
ABL
Abnormality involves a chromosomal translocation 9:22 to the BCR gene. This produces a chimeric, constitutively active tyrosine kinase
What is the genetic abnormality that results in Burkitt lymphoma
Chromosomal translocation of MYC gene 8:14, resulting in increased production of MYC protein
What type of malignancies are associated with JAK2 abnormalities, and by what mechanism? What type of protein is JAK2, and what what type of genetic abnormality is usually associated with it
Myeloid neoplasms. This is because JAK2 becomes constitutively active and no longer needs signalling from haematopoeitic growth factors such as EPO.
JAK2 is a nonreceptor tyrosine kinase (other non tyrosine receptors on the cell membrane receive the growth factor)
Point mutations
What are mature cells of lymphoid origin
NK cells
B cells
T cells
What are mature cells of myeloid origin
Platelets, erythrocytes (red cells), basophils, eosinophils, neutrophils, monocytes
What are the three categories of myeloid neoplasm
Acute myeloid leukaemia: immature progenor cells accumulate in the bone marrow
Myelodysplastic syndromes: ineffective haematologists resulting in peripheral cytopenias
Myeloproliferative syndromes: increased production of one or more terminally differentiated cell lines
How are lymphocytic lymphomas vs leukaemia defined in basic terms
By the usual distributions of the disease:
-leukaemia: starts in bone marrow, spills out into peripheral blood
-lymphoma: form discrete tissue masses
There can be cross over in presentations, particularly in advanced disease
What are the subtypes of Hodgkin lymphoma
Classical:
-nodular sclerosing
-mixed cellularity
-lymphocyte rich
-lymphocyte depleted
Nodular lymphocyte predominant
What type of lymphoid neoplasm is follicular lymphoma
A peripheral B cell neoplasm
What are the 5 classification groups of lymphoid neoplasms
- Precursor B-cell neoplasms (B-ALL)
- Peripheral B-cell neoplasms
- Precursor T-cell neoplasms (T-ALL)
- Peripheral T-cell neoplasms
- Hodgkin lymphoma
What is the difference between Hodgkin lymphoma and NHL in terms of their typical distribution at diagnosis and pattern of spread
Hodgkin lymphoma sometimes presents in a single group of lymph nodes only.
Tend to spread in an orderly fashion. Lymph nodes, then spleen, then liver, then bone marrow + other tissues
Extranodal presentation is rare. Rare to involve waldeyer ring or mesenteric nodes
NHL more likely to present as disseminated disease and unpredictable
What is included in the waldeyer ring
Adenoid bands
Tubal tonsils ( located posterior to the opening of Eustachian tubes)
Palatine tonsils
Pharyngeal tonsils/band
Lingual tonsils
What cells are characteristic of Hodgkin lymphoma
Reed Sternberg cells: neoplastic giant cells with owl eye appearance
What type of cell are Reed Sternberg cells derived from
Post germinal centre B cells
What makes up most of the cellularity of Hodgkin lymphoma
Lymphocytes, macrophages, granulocytes recruited by reed Sternberg cells
What is the average age of diagnosis of Hodgkin lymphoma
32 years old
Why is nodular lymphocyte predominant Hodgkin lymphoma not considered classical lymphoma
The reed Sternberg cells have a different immunophenotype
Do Reed-sternberg cells commonly express B-cell genes
No, presumably due to widespread epigenetic change
Why is T-cell immune response again Reed-Sternberg cells commonly not effective
Due to increased copy number (therefore expression) of PD-L1 and PD-L2 to inhibit T-cell activation
What is the appearance of Reed-Sternberg cells
Large cells with binucleation
Each nucleus has large inclusion-like nucleoli
Abundant eosinophilic cytoplasm
Prominent nuclear membrane
Perinuclear halo
Multiple variants exist
How is Hodgkin lymphoma distinguished from other conditions that have Reed-Sternbeg-like cells
The presence of Reed-Sternberg cells surrounded by background of non-neoplastic cells (confirmed by IHC)
What is the IHC profile of classical Hodgkin lymphomas
CD15+ CD30+ PAX5+
CD45-
What is the IHC profile of nodular lymphocyte predominant Hodgkin lymphoma
CD20+ BCL6+
CD15- CD30-
What is the most common subtype of Hodgkin lymphoma
Nodular sclerosis (65-70% of cases)
What variant of Reed-Sternberg cells are seen in nodular sclerosis Hodgkin lymphoma
Lacunar cells: nucleus sitting in large empty space (as a result of processing process to produce slides)
What are the microscopic features of nodular sclerosis Hodgkin lymphoma
Lacunar Reed Sternberg cells
Infiltrate of T cells, eosinophils, macrophages, plasma cells
Fibrous bands of collagen deposition resulting in involved lymph nodes being divided up into discrete nodules
Usually EBV -ve
What is PAX5
A B cell transcription factor
What is the prognosis of nodular sclerosis Hodgkin lymphoma
Excellent
How does mixed cellularity Hodgkin lymphoma differ from nodular sclerosis in terms of histological features
Reed Sternberg cells frequent
Commonly EBV +ve
What is the typical clinical presentation of nodular sclerosis Hodgkin lymphoma
Young age
Mediastinal disease common
M=F
What is the typical clinical presentation of mixed cellularity Hodgkin lymphoma
Older age(biphasic young age and middle age)
Present with more advanced stage disease
M>F
Presence of what virus is associated with Hodgkin lymphoma
EBV, varies in rates of positivity depending on subtype
What are the histological features of nodular lymphocyte predominant Hodgkin lymphoma
“Popcorn cells” rather than typical Reed-Sternberg cells
Lymphocyte and macrophage infiltrates
What is the typical presentation of nodular lymphocyte predominant Hodgkin lymphoma
M>F
Young age (<35)
Cervical or axillary lymphadenopathy
Prognosis excellent
What staging system is used for Hodgkin Lymphoma
Ann Arbor staging
-see Robbins page 615
What malignancy appears to be most responsive to immune checkpoint inhibitors
Hodgkin lymphoma
What is the typical presentation of B- acute lymphoblastic lymphoma/leukaemia
Presents as a leukaemia in childhood
What is the typical presentation of acute T-cell acute lymphoblastic leukaemia/lymphoma
Presents as a thymus lymphoma in adolescence
What gene in mutated by chromosomal aberrations in almost all T-cell ALL
NOTCH1
What percentage of ALL have chromosomal abnormalities, and what what is the most common aberration?
90%
Most common is hyperploidy (increased numbers of chromosomes, often >50
What are microscopic features of ALL
Scanty basophilic cytoplasm
Nuclei larger than normal lymphocytes, small nucleoli.
Nuclear membrane frequently subdivided
High mitotic rate
“Starry sky” appearance from macrophages Ingesting apoptotic cells
On immunophenotyping how is ALL distinguished from AML
TdT (terminal deoxynucleotidyl transferase) is expressed only in pre-B and pre-T lymphoblasts
What are the immunophenotypes of immature and more mature B-ALL
Immature: CD19, PAX5,CD10 +/-
More mature: CD10, CD19, CD20, pax5
What are the typical immunophenotypes of very immature and more mature T-ALL
Maturity independent: CD1, CD2, CD5
More mature: CD3, CD4, CD8
What malignancies have the chromosomal 9:22 translocation. What is the resulting gene fusion, and what is the therapeutic relevance
AML and some B-ALLs
Results in BCR-ABL fusion, resulting in constitutional tyrosine kinase activity of ABL.
There is an inhibitor for this fused tyrosine kinase, Imatinib, which dramatically improves survival
What anti apoptotic protein is uniformly over-expressed in CLL (chronic lymphocytic leukaemia).
BCL2
The NOTCH1 receptor frequently has gain of function mutations
What is the microscopic appearance of CLL
Lymph nodes Small lymphocytes with round nuclei and scant cytoplasm
Pathopnemonic: ‘proliferation centres’ containing larger activated lymphocytes
Smudge cells on blood smears of peripheral blood (cells disrupted in process of making smears)
What is the typical immunophenotypes of CLL
CD19, CD20, high levels expression of BCL2
What is the rate of transformation of CLL to high grade lymphoma, and what are common mutations involved
5-10%
P53 and MYC
What chromosomal translocation is a hallmark of follicular lymphoma
14:18
Involves BCL2 gene, leading to over expression of BCL2
What cancers are associated with BCL2 over expression, and by what mechanisms
Follicular lymphoma: chromosomal translocation involving BCL2 gene 14:18
DLBCL: same translocation as follicular lymphoma, in 10-20%
CLL: deletions involving genes that have downstream effects leading to increased expression of BCL2
What are microscopic features of lymph nodes involved by follicular lymphoma
Lack of apoptotic cells in germinal centres
Nodular or diffuse growth pattern
Two cell types:
Centrocytes: small cells with scanty cytoplasm, cleaved/ irregularly contoured nuclei
Centroblasts: larger cells, open nuclear chromatin, several nucleoli, modest cytoplasm
What is the typical immunophenotypes of Follicular lymphoma
Positive: CD20, CD19, CD10, BCL6
Negative: CD5
BCL2 positive (negative in normal germinal centres)
What percentage of follicular lymphomas transform to high grade lymphoma
30-50%
Usually with increased expression of MYC