Skip to Main Content

++

Malignant lymphomas—primary neoplasms of lymphoid tissue derived from lymphocytes—occur as solid tumors, usually within lymph nodes and less often in extranodal lymphoid tissues such as the tonsil, gastrointestinal tract, and spleen.

++

Malignant lymphomas are classified as non-Hodgkin's lymphomas, which are derived from lymphocytes, and Hodgkin's lymphomas. Hodgkin's lymphomas have retained their eponymous designation because the cell of origin remains uncertain.

++

Lymphoma versus Leukemia

++

Neoplastic lymphocytes circulate (mimicking normal lymphocytes) and frequently are found widely distributed throughout the lymphoid tissues. If bone marrow involvement and circulating cells predominate or if they constitute the first recognized manifestation of the disease, the process is termed leukemia. If the proliferation dominantly affects the lymphoid tissues or if a tissue mass is the presenting feature, the process is termed lymphoma. This distinction is arbitrary, and in children the term lymphoma-leukemia is sometimes used for two reasons. The two forms may coexist and lymphoma frequently evolves toward a leukemic state (Table 29-1).

++
Table Graphic Jump Location
Table 29–1. Sites of Involvement in Lymphoma-Leukemia.  
++

Malignant Lymphoma versus Benign Lymphoma

++

The observation that neoplastic lymphocytes circulate extensively—coupled with widespread tissue involvement in many cases—has resulted in classification of all of these conditions as malignant lymphomas. This obscures the fact that many malignant lymphomas have relatively benign biologic behavior (ie, are slow-growing and compatible with long survival). The widespread distribution of the disease in the body represents mimicry of normal lymphocyte circulation rather than metastatic potential. Neoplastic proliferation of lymphocytes confined to one area of the body without the potential for dissemination—to which the term benign may truly be applied—occurs rarely, if at all.

++

Incidence of Non-Hodgkin's Lymphomas

++

Leukemias and lymphomas, including Hodgkin's lymphoma, account for approximately 8% of all malignant neoplasms and together represent the sixth most common type of cancer. Leukemia-lymphoma is the most common malignant neoplasm of children in the United States. About 25,000 cases of non-Hodgkin's lymphoma occur annually in the United States. The relative incidence of the subtypes of lymphoma varies greatly with age (Table 29-2) and to a lesser extent with sex and geographic factors.

++
Table Graphic Jump Location
Table 29–2. Relative Incidence of Lymphomas in Adults and Children.  
++

Etiology of Non-Hodgkin's Lymphomas

++

In many animals, lymphoma and leukemia have a viral etiology. Murine, feline, and avian leukemias all are caused by retroviruses (type C), while Marek's ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessPhysiotherapy Full Site: One-Year Subscription

Connect to the full suite of AccessPhysiotherapy content and resources including interactive NPTE review, more than 500 videos, Anatomy & Physiology Revealed, 20+ leading textbooks, and more.

$595 USD
Buy Now

Pay Per View: Timed Access to all of AccessPhysiotherapy

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.