95 Pathology of Lymphomas Flashcards
Four main groups of lymphoid malignancies
- Precursor B- and T-cell neoplasms
- Mature B-cell neoplasms
- Mature T- and natural killer (NK)-cell neoplasms
- Hodgkin lymphomas
The cornerstone of lymphoma diagnosis of lymphoma where assessment of lymph node architecture and cell morphology is performed
Hematoxylin-eosin stain
Are neoplasms of precursor lymphoid cells committed to the B or T lineage.
Lymphoblastic leukemia/lymphomas
Most cases of lymphoblastic lymphoma are of _______lineage
T-cell lineage
Common site of involvement of lymphoblastic lymphoma
Mediastinum
MORPH: small- to intermediate-size cells with finely dispersed nuclear chromatin, inconspicuous nucleoli, and scant cytoplasm
PRECURSOR LYMPHOID NEOPLASMS
Immature markers of lymphoblastic neoplasms:
- Terminal deoxynucleotide transferase, CD1a, and/or CD99
- B Cell: CD19, CD79, and CD22
- T Cell: CD3 and CD7
A neoplasm composed of monomorphic mature B lymphocytes that coexpress CD5 and CD23
Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL)
Disease presents with monoclonal B-lymphocyte counts greater than or equal to 5 × 109/L in the blood
CLL
Present clinically with lymphadenopathy or tissue disease with a number of blood monoclonal lymphocytes less than 5 × 109/L
SLL
Immunophenotype of CLL/SLL
CD5 and CD23 expression, dim expression of CD20, and weak surface clonal immunoglobulin chains
Epigenetic subtype of CLL and prognosis
- Naïve B lymphocytes (naïvelike): unfavorable
- Memory B lymphocytes (memorylike): favorable
- Intermediate: intermediate
Most common genetic alterations in CLL
- deletions in 13q14.3
- trisomy 12
- deletions of 11q22-24 (ataxia-telangiectasia mutated gene [ATM])
- del 17p13 (the gene coding for tumor protein p53 [TP53])
Associated with transformation/Richter syndrome
TP53 and NOTCH1 mutations, MYC translocations, and homozygous deletions of CDKN2A
A neoplasm of small B lymphocytes with plasmacytoid features, usually involving marrow and sometimes spleen, lymph nodes, and, less often, blood
Lymphoplasmacytic lymphoma
Lymphoplasmacytic lymphoma is often associated with this monoclonal immunoglobulin that can cause hyperviscosity or cryoglobulinemia (Waldenström macroglobulinemia)
Monoclonal immunoglobulin M serum protein
A commonly recurring and highlyspecific feature of Waldenström macroglobulinemia
MYD88
Mutations in CXCR4 are present in a minority of cases
MORPH: small lymphocytes and cells with plasmacytoid features (eccentric nuclei and bluish cytoplasm)
LYMPHOPLASMACYTIC LYMPHOMA
A mature B-cell lymphoma typically composed of monomorphic small- to medium-size lymphocytes with irregular nuclei that express CD5 but are negative for CD23
Mantle cell lymphoma (MCL)
It most commonly has a diffuse growth pattern, but it can show annodular or, more rarely, a mantle zone pattern
Mantle cell lymphoma (MCL)
associated with gastrointestinal tract (lymphomatous polyposis)
Translocation in Mantle cell lymphoma (MCL)
t(11;14)(q13;q32) translocation which results in the expression of cyclin D1
Protein whose expression is also highly specific to MCL, can be used as an immunohistochemical marker to diagnose cases that are negative for cyclin D1
SOX11
Condition where Cyclin D1–positive lymphocytes in mantle zones can be an incidental finding in reactive lymphoid follicles
In situ mantle cell neoplasia
Very indolent behavior and do not require treatment
A neoplasm composed of germinal center B cells (GCBs) with a variable mixture of centrocytes and centroblasts
Follicular lymphoma (FL)
The cells retain expression of germinal center markers (BCL6, CD10, LMO2), and demonstrate a nodular architecture
Follicular lymphoma (FL)
FL can be graded (grades 1–3) based on the number of centroblasts present within the nodules.
Both grade 1 and grade 2 tumors are indolent, and distinguishing between them is generally not helpful.
Grade 3 lesions (>15 centroblasts per high-power microscopic field) can be further divided into:
- grade 3A (centroblasts and centrocytes both present)
- grade 3B (depletion of small centrocytes).
Mutation common in Follicular lymphoma (FL)
t(14;18)(q32;q21)
involving rearrangement of the BCL2 gene