Large Granular Lymphocyte Leukemia/Lymphoma in Six Cats

Abstract

This report describes six cases of feline large granular lymphocyte lymphoma identified by light microscopy on the basis of their characteristic azurophilic granulation in Giemsa-stained plastic sections and by electron microscopy on the basis of their typical granules. Although the granules of all the tumor cells were negative for peroxidase activity, they all demonstrated chloroacetate-esterase and acid phosphatase activity. All the tumors reacted with cross-reacting antibodies against the CD3 antigen (epsilon chain) and did not react with a cross-reacting monoclonal antibody directed against epitopes on cytoplasmic domains of the CD20 antigen. Three tumors had a positive reaction with a monoclonal human CD57-like antibody. This is highly suggestive of either a cytotoxic T cell or a natural killer cell origin of the neoplasias. In three cats, although other abdominal organs were affected to a variable extent, the main neoplastic lesions were localized in the gastrointestinal tract and the jejunal lymph nodes. In contrast, in the other three cats, organ involvement was more widespread, affecting the lung (two), myocardium (two), precardiac mediastinum (one), salivary gland (one), and spinal cord (one); in addition, leukemia was present in two of these cats. The data presented indicate that tumors made up of large granular lymphocytes occur more frequently in cats than previously assumed and that they share many characteristic features with specific subtypes of clonal disorders of large granular lymphocytes in humans.

Systemic T Cell Large Granular Lymphocyte Lymphoma with Multifocal White Matter Degeneration in the Brain of a Japanese Domestic Cat

“…Clinical and pathological features of the present case are almost identical to those in the previous reports of feline LGL lymphomas [4,9,10,13,15,17]. The diagnosis of LGL lymphoma was confirmed by the results of cytology and immunohistochemistry.…”

“…The present case indicates that the combination of CD3-and granzyme B-immunostains is useful for the pathological diagnosis of feline LGL lymphoma. Previous studies [4,9,10,13,15,17] dealing with feline systemic T cell/LGL type lymphomas mentioned that the alimentary tract might be the primary region, although the exact origin of the tumor is not confirmed. In the present case, neoplastic cells were observed in almost all organs, including the CNS.…”

“…The neoplastic cells are of either T-cell or natural killer (NK)-cell lineage, which are indistinguishable by cell morphology [4,9,11,19]. Immunohistochemically, however, LGL cells are classified into 2 types; the CD3-positive Tcell type and CD3-negative natural killer-cell type [19].…”

Large granular lymphoma in six cats

“…However, in any case presented here this abnormality was present, probably because of segmental, but not diffuse involvement of the small intestine was observed. The presence of neoplastic cells in peripheral blood is a typical feature of feline large granular lymphomas, sometimes leukocytosis is marked, reaching 70000 white blood cells per μl of blood (Karyia et al 1997, Darbes et al 1998, Roccabianca et al 2006. Surprisingly, leukocytosis was observed only in 2 of 6 cats in this study; however, even in these animals, elevation of leukocyte number was mild and was related to increased granulocyte count, without the presence of neoplastic cells in the blood.…”

Oral Cavity, Gastrointestinal Tract, and Associated Structures

“…Lymphoma readily exfoliates, which facilitates a cytologic diagnosis ( Fig. Lymphoma composed of large granular lymphocytes often involves the intestinal tract and jejunal lymph nodes thus making these suitable potential organs for cytologic examination (Darbes et al, 1998). Franks et al (1986) published the clinical, cytologic, histologic, and ultrastructural findings of feline large granular lymphoma.…”