WBC Flashcards
Lymphomas are
malignant proliferations of cells native to lymphoid tissue – lymphocytes and their precursors and derivatives.
Lymphomas usually arise in
lymphoid tissue, and can spread to involve solid tissue, marrow, and blood.
Lymphomas are categorized into two main types–
Hodgkin and non-Hodgkin lymphomas.
Leukemias are malignant proliferations of cells native to the
bone marrow, which often spillover into the blood. Leukemias can spread to involve solid organs (usually liver and spleen).
Until 1973, ethnic pigmentation was
unhealthy - if it wasn’t pink, it’s bad. This has gone by.
The distinction between lymphoma and the lymphocytic leukemias can be difficult in some instances, since in advanced states both can involve
lymphoid tissue at any site.
Hodgkin lymphoma: This is a characteristic type of lymphoma defined morphologically by the presence of
Reed-Sternberg cells admixed with a variable inflammatory infiltrate.
Unlike non-Hodgkin lymphomas, Hodgkin lymphoma (HL) is often accompanied by
fever, arises in a single lymph node or chain of nodes, is more common in young adults (average age 30 years), and is characterized by contiguous spread within lymph node groups (for this reason, staging is particularly important in assessing prognosis).
The cause of Hodgkin lymphoma is unknown, but
EBV has been implicated in playing a role.
Hodgkin Lymphoma: Cell of Origin: The neoplastic cell is the
Reed-Sternberg (RS) cell, a distinctive large cell with mirror image nuclei and prominent nucleoli.
Usually only small numbers of RS cells are present in the
involved node.
A diagnosis of Hodgkin lymphoma requires the presence of RS cells in the appropriate
histologic background: RS-like cells alone are not specific, and may be seen in non-neoplastic disorders like infectious mononucleosis.
RS cells may arise from specialized
antigen-presenting cells in lymph nodes; the precise origin of the RS cell remains uncertain. I
in some cases the Epstein-Barr virus genome can be identified in the
RS cells.
Hodgkins:
Classification (Grading):
Several variants of Hodgkin lymphoma are recognized each with their own common clinical presentations, histologic features, and (to a certain extent) prognosis. Spread of disease is predictable: lymph nodes,spleen
Liver, bone marrow.
Staging: Staging is used to determine treatment and prognosis
1.
I - Tumor in one anatomic region or two contiguous anatomic regions on the same side of the diaphragm
Staging: 2
II - Tumor in more than two anatomic regions or two non-contiguous regions on the same side of the diaphragm
Staging 3:
III - Tumor on both sides of the diaphragm not extending beyond lymph nodes, spleen or Waldeyer’s ring
Staging 4:
IV - Tumor in bone marrow, lung, etc.- any organ site outside of the lymph nodes, spleen or Waldeyer’s ring
“B” signs/symptoms:
Hodgkins
Fever, night sweats, and significant unexplained weight loss
Low-stage disease denotes
localized lymph node involvement, without systemic signs (fever, weight loss), and has a better prognosis.
High-stage disease indicates
widespread disease, often with bone marrow involvement, and has a worse prognosis.
Choice of therapy (chemotherapy, radiotherapy, or both) and prognosis are based on
stage.
More aggressive forms of disease typically present in
higher stages.
Treatment consists of a combination of
chemotherapy and, to a less extent today, radiotherapy.
All stages are further divided on the basis of
absence (A) or presence (B) of systemic symptoms, including fever, night sweats, and significant unexplained weight loss (terminology example: stage IIIA).
Hodgkins Bimodal age distribution:
20-30 years old and >50 years old, ~8,300 cases in 2017, Painless lymphadenopathy (often cervical, supraclavicular, mediastinal), Splenomegaly (detected by MRI)
Hodgkins: Most patients have
enlarged, painless, superficial lymph node in
ivolvement as the initial manifestation of disease. Involvement of other lymph nodes in the chest and abdomen can occur, but is less common at presentation, except in lymphocyte-depleted type.
Hodgkins: Involvement of the spleen and liver increase
the stage, and are assessed by MRI.
Hodgkins: Complications with
infections (decreased cell-mediated immunity), anemia, and thrombocytopenia can occur in advanced disease.
Combination chemotherapy and, to a lesser extent, radiotherapy have
dramatically improved the survival in HD.
There is a low, but definite risk for developing
acute leukemia after treatment with chemotherapy and radiotherapy because of the bone marrow toxicities of the chemotherapeutic drugs used.
Prognosis - hodgkins
5-year survival - Stage 1 and IIa
Stage I and IIA - almost 100%
Hodgkins: 5-year survival rate in Stage IV is
50%
“B” signs/symptoms associated with worse prognosis
Stage III and IV disease more likely to have
“B” symptoms (worse prognosis)
Non-Hodgkin lymphomas (NHL) arise in
lymphoid tissue – either in lymph nodes or lymphoid tissue of solid organs- and have the capacity to spread into other nodes, solid organs, bone marrow, and blood.
NHL: Over 2 dozen
types are currently recognized. Most (85%) are of B cell origin. Most of remainder are of T cell origin
Incidence rises steadily after age 40, approximately 72,000 cases in 2017.
NHL :There is more morphologic diversity in NHL than in
HD, and more than two dozen subtypes of NHL are recognized for purposes of determining prognosis and selecting therapy.
NHL: 8 of the subtypes comprise over
90% of the NHLs in the US.
In contrast to HD, NHLs tend to have
multiple node involvement, more frequent extranodal spread and peripheral blood involvement, and affect all ages.
Like HD, histologic examination of involved tissue is
required for diagnosis.
Cell of Origin: The majority (85%) of NHL are
clonal neoplasms of B lymphocytes.
B lymphocytes are those lymphocytes specialized for
antibody production.
The remainder of NHL are of
T cell origin (15%).
B-lymphocytes normally have the capacity to differentiate into
plasma cells (the most mature B cell) as part of the immune response, just as T-lymphocytes become activated as part of the normal immune response.
A lymphoma develops when there is a
monoclonal expansion of lymphocytes that have been “arrested” (or have acquired a genetic rearrangement that alters growth regulation) at a particular stage in transformation. The clonal cells proliferate without normal regulatory mechanisms.
Thus, all lymphoid neoplasms are considered to arise from a
single transformed cell. daughter cells synthesize antigen receptor proteins identical to the original cell that reflect a “frozen” state of B cell maturation.
(hypogammaglobulinemia,
increased risk of infection).
NHLs are classified on the basis of their
morphology (microscopic appearance), cell of origin (immunophenotype), clinical features, and genotype.
The World Health Organization convenes panels of lymphoma experts to examine the accuracy and utility of the classification system, and the most recent system, published in 2008, is based on the
Revised European-American Lymphoma classification that was first proposed in the mid-1990’s.
Staging: NHL: Similar to Hodgkin lymphoma. There is less correlation between
stage and prognosis in NHL than in HD. Cell type and tumor proliferative index are better correlated with prognosis.
NHL: • Localized disease indicates what stage-
low stage