Etiology:  Malignant lymphomas arise from lymphocytes and their precursors.  They can be categorized into seven types.  Small lymphocyte, lymphoblastic, pleomorphic/follicular, plasmacytic, immunoblastic, marginal zone and not otherwise specified (NOS).

Incidence:  Malignant lymphomas are common in certain strains/stocks of mice.

Clinical Signs:  Often there are no clinical signs associated with lymphoma.

Pathology:  Malignant lymphomas are usually systemic tumors, and are most common in the mesenteric lymph nodes and spleen.  Grossly, the spleen and mesenteric lymph node are enlarged and may have tan discoloration (picture).  There may be liver or multiple lymph node involvement in more advanced cases.  Histologically, tumor features are dependent on the type of lymphoma [1].

Diagnosis:  Diagnosis can be made upon necropsy and histopathologic examination of tissue.

1.            Pathology Of The Mouse. 1 ed1999, 2850 Oak Grove Road, Vienna, IL, 62995: Cache River Press.