HEMA 2 LEC - Mature Lymphoid Neoplasms Flashcards
• monoclonal proliferation of terminally differentiated B cells (i.e., plasma cells)
plasma cell neoplasms
• multifocal accumulation of malignant plasma cells in the bone marrow presenting as lytic bone lesions
plasma cell neoplasms
• encompass the entire patient population with clonal serum immunoglobulin and only mild marrow plasmacytosis.
Monoclonal gammopathy of undetermined significance (MGUS):
a localized form of plasma cell neoplasm, may present as a solitary bone lesion or involve an extraosseous or extramedullary site, most commonly the nasopharynx, oropharynx, or sinuses
Plasmacytoma
- marked bone marrow plasmacytosis.
* Large aggregates and sheets of plasma cells,
plasma cell neoplasms
high nuclear-to-cytoplasmic ratio, dispersed chromatin pattern, and distinct nucleoli
plasma cell neoplasms
: for cases > 20% circulating plasma cells or plasma cell counts exceeding 2 109/L.
Plasma cell leukemia
• what cells are positive for CD138 (syndecan 1), high-density CD38 antigen, and monoclonal cytoplasmic immunoglobulins
Plasma cells
clinical features • Bone pain and pathologic fractures • Renal insufficiency • Cytopenias • Depressed normal immunoglobulin levels
plasma cell neoplasms
• Tissue deposits of clonal immunoglobulins is called
amyloidosis
• High levels of serum immunoglobulins → interfere with the coagulation cascade → impair circulation through an increase in serum viscosity
what condition
plasma cell neoplasms
• Defining feature: large cell size
Diffuse Large B-Cell Lymphoma
• Shows a diffuse proliferation of large lymphoid cells replacing the normal lymph node architecture
Diffuse Large B-Cell Lymphoma
• Cells at least twice the size of normal small lymphocytes and show single or multiple nucleoli and ample cytoplasm
Diffuse Large B-Cell Lymphoma
• Characterized by medium- sized, highly proliferating lymphoid cells with basophilic vacuolated cytoplasm
Burkitt lymphoma
3 variants of Burkitt lymphoma WHO classification lists
o Endemic (occurring predominantly in Africa) o Sporadic o Immunodeficiency associated
• Lymphoid proliferation: diffuse, shows a prominent “starry sky” pattern (low magnification) imparted by numerous tingible body macrophages
Burkitt lymphoma
• Hallmark of Burkitt lymphoma =
high proliferation rate.
how many percent of Burkitt lymphoma cells are actively proliferating
100%
constitutive expression of MYC gene (cell cycle gatekeeping gene) secondary to its translocation under the promoter of immunoglobulin heavy or light chain genes, t(8;14), t(2;8), t(8;22)
Burkitt Lymphoma
gene expressed in Burkitt
MYC gene
variant of Burkitt lymphoma in young children (4 to 7 years of age), most commonly as a jawbone mass
Endemic
variant of Burkitt lymphoma >seen in the United States and Europe, occurs in children and young adults most commonly as an abdominal mass
Sporadic
variant of Burkitt lymphoma
presents most often as nodal disease; occurs predominantly in HIV- positive patients
Immunodeficiency-associated
variant of Burkitt lymphoma
Gastrointestinal tract and abdominal lymph nodes are often involved however, other extranodal sites, such as gonads and breasts, can be a site of primary disease
Sporadic
commonly involves the central nervous system, bone marrow, and peripheral blood (Burkitt leukemia).
Burkitt leukemia
virus present in Burkitt Lymphoma
Epstein-Barr virus (EBV)
Much less common
Shows geographic and ethnic variability
Mature T-Cell and Natural Killer Cell Lymphomas
• T-cell neoplasms occur more frequently in
extranodal sites
Phenotype (B or T cell) of mycosis fungoides
T cell
most common skin lymphoma
mycosis fungoides
Small to medium-sized lymphoid cells with irregular nuclear outlines (cerebriform nuclei)
Show a predilection for the epidermis (epidermotropism) and dermis
mycosis fungoides
presents as a disseminated disease with widespread skin involvement (erythroderma), lymphadenopathy, and circulating lymphoma cells (Sézary cells with characteristic cerebriform nuclei)
Sézary syndrome
In mycosis fungoides, the colonization of epidermis by neoplastic lymphocytes is seen with small aggregates of lymphoma cells forming so-called
Pautrier microabscesses
important immunophenotypic feature of mycosis fungoides
absence of CD7 antigen
How many sezary cells to be classified as sezary syndrome
at least 1000 Sezary cells/mm^3
CD4 to CD8 ratio to be classified as sezary syndrome
more than 10
aggressive lymphoma with skin and lymph node involvement
sezary syndrome
Morphologically heterogeneous group of lymphomas with mature T-cell phenotype
Peripheral T-Cell Lymphoma, Unspecified
- Lymph node involvement: usually diffuse with a prominent vascular proliferation
- Cytologic features are variable with medium-sized to large cells with atypical and occasionally pleomorphic nuclei
Peripheral T-Cell Lymphoma, Unspecified
- Generalized lymphadenopathy
* Constitutional symptoms: fever, night sweats, weight loss, and pancytopenia
Peripheral T-Cell Lymphoma, Unspecified