Lymphoid Neoplasia

Chapter 27 Lymphoid Neoplasia

The lymphoproliferative disorders presented here are characterized by neoplasia involving cells or cell lines of lymphoid origin, including lymphoma, lymphoid leukemia, multiple myeloma, and plasmacytoma. Because of differences in diagnosis, therapy, and prognosis among these conditions, they are discussed here as separate entities.


Lymphoma (lymphosarcoma) is defined as a lymphoid neoplasm primarily affecting lymph nodes or other solid visceral organs such as the liver or spleen. It is the most common of the lymphoproliferative disorders in small animals. Middle-aged to older dogs primarily are affected without sex predilection. Although lymphoma can occur in any purebred or mixed-breed dog, it may be more prevalent in golden retrievers, German shepherds, boxers, poodles, bassets, and Saint Bernards.

No breed predilection exists for cats; however, several reports have observed a 1.5:1 male-to-female ratio. Affected cats that are feline leukemia virus (FeLV) antigenemic tend to be younger (median age 3–5 years) than FeLV-negative cats (median age 7–10 years).

Classification and Clinical Signs

Traditionally, lymphoma is classified based on anatomic site. Clinical signs vary with the sites involved. In cats, the frequency of anatomic forms associated with FeLV antigenemia (i.e., mediastinal and multicentric forms) has declined along with the declining frequency of FeLV-associated lymphomas. Whereas these sites made up the bulk of cases observed in cats before 1985, they are now in the minority. Currently, the alimentary form, which only rarely is associated with FeLV antigenemia, makes up the bulk of lymphomas in cats. Other less common forms occurring in cats include renal, hepatic, and miscellaneous extranodal sites.

World Health Organization (WHO) clinical staging of lymphoma also can be used to classify the extent of the disease (Table 27-1).


Stage Criteria
I Involvement limited to single lymph node or lymphoid tissue in a single organ (excluding bone marrow)
II Involvement of many lymph nodes in regional area (with or without tonsils)
III Generalized lymph node involvement
IV Liver and/or spleen involvement (with or without stage III)
V Manifestations in blood and involvement of bone marrow and/or other organ systems (with or without stages I–IV)

* Reprinted with permission from World Health Organization: Owen LN: TNM Classification of Tumors in Domestic Animals. Geneva: WHO, 1980.

Each stage is subclassified into (a) without systemic signs and (b) with systemic signs.


The diagnosis of lymphoma is based on a complete history, physical examination, tissue diagnosis, and clinical staging. Clinical staging should include a complete blood count (CBC), platelet count, bone marrow aspiration or core biopsy, biochemistry profile, and thoracic and abdominal radiographs. Abdominal ultrasound can be added to the workup if indicated based on presentation.

Laboratory Evaluations

Aug 27, 2016 | Posted by in SMALL ANIMAL | Comments Off on Lymphoid Neoplasia
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