April 2018

Signalment:  2-year-old male castrated domestic longhair cat

HISTORY:  This cat was feline leukemia virus positive.

HISTOPATHOLOGIC DESCRIPTION:  Lymph node:  Diffusely effacing the cortex and medulla is an infiltrative, densely cellular neoplasm composed of diffuse sheets of large lymphocytes on a pre-existing fibrovascular stroma.  Neoplastic cells have distinct borders and scant eosinophilic granular cytoplasm.  Nuclei are large and irregularly round with coarsely stippled chromatin, and 1-2 prominent nucleoli.  Mitoses average 6 per individual high power field.  Multifocally, neoplastic cells are within vessels and there is scattered single cell necrosis.  Subcapsular and medullary sinuses contain moderate hemorrhage, small amounts of fibrin, increased numbers of histiocytes (sinus histiocytosis) that multifocally contain phagocytized erythrocytes and hemosiderin. The capsule and perinodal adipose tissues are mildly expanded by variable amounts of hemorrhage, lymphocytes and macrophages, rare neutrophils, and mild edema.

MORPHOLOGIC DIAGNOSIS:  Lymph node:  Lymphoma, diffuse, large, intermediate grade domestic longhair, feline.

CAUSE:  Feline leukemia virus (FeLV)

ETIOLOGIC DIAGNOSIS:  Feline retroviral lymphoma








COMPARATIVE PATHOLOGY:  (Viral-induced lymphomas)


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