Lymph Nodes Flashcards
Reactive hyperplasia
- broad term that encompasses all benign, reversible enlargement of the lymphoid tissue secondary to an antigenic stimulus.
- nodal response to antigenic stimuli is highly variable and can be classified as follicular hyperplasia, sinus hyperplasia, or diffuse hyperplasia.
- polyclonal in that it consists of a proliferation of many different cell types within the lymph node.
Pleomorphism, increased mitoses, and nuclear changes
Follicular hyperplasia
when the follicles increase in size and number,
sinus hyperplasia
when the sinuses enlarge and fill with histiocytes.
Diffuse hyperplasia
observed when the nodal architecture is diffusely effaced by sheets of lymphocytes, immunoblasts, and macrophages.
Malignant.
as in lymphomas), the normal lymph node architecture is distorted or effaced by the proliferation of malignant lymphoid cells, often to a greater extent than that seen with reactive hyperplasia.
Malignancy-associated effacement of nodal architecture may be follicular or diffuse.
- monoclonal in that it results from the unchecked proliferation of a single genetically unique cell from only one cell line.
- A predominantly monomorphic cell population is indicative of malignancy and is characteristic of non-Hodgkin’s lymphoma
Hodgkin’s lymphoma does demonstrate an admixture of several lymphoid cell types within the lymph nodes; however, this finding does not distinguish Hodgkin’s lymphoma from reactive hyperplasia.
Evaluation for monoclonality of the lymphocyte population is important when lymphoma is suspected
- clonality of a T-cell population is assessed by molecular methods, such as PCR, that examine the rearrangement of T-cell receptor (TCR) genes.
—If a single allele for the V region of the T-cell receptor predominates in a lymphocytic population, monoclonal proliferation is suspected - Monoclonal rearrangement of the genes for immunoglobulin variable regions is suggestive of a B-cell lymphoma.
