A Neoplasm of Globule Leukocytes in a Cat

Abstract

Abstract.A neoplasm involving the ileo-cecal-colic junction, thymus, and tracheobronchial lymph nodes of a 7-year-old domestic cat was composed of dense sheets of round to oval mononuclear cells with oval to indented nuclei, moderate amounts of cytoplasm, and variable numbers of round eosinophilic granules. These granules are brown to black in phosphotungstic acid hematoxylin-stained sections and stain variably with the periodic acid-Schiff stain. They are 0.8 to 1.5 pm in diameter, limited by a single unit membrane, and have variable electron density. Light microscopic cellular morphology and staining characteristics as well as ultrastructural features of these cells are consistent with feline globule leukocytes. Morphologic features of the neoplastic cells in the present case are similar to those of the only other reported neoplasm of globule leukocytes which also involved the intestine of a cat.Globule leukocytes are found in the mucosa of the intestinal, respiratory, and urogenital systems of many species. 2,13,23,24 Although first described in 19 1 9,2y their origin and function remain controversial. Derivation of globule leukocytes from lymphocytes, 14,25 plasma eo~inophils,~ and a unique mesenchymal cell population23 has been suggested. Recent investigation has focused on the mast cell as a possible source of globule leukocytes. In the digestive tract, derivation of the globule leukocyte from the submucosal mast cell has been proposed.17 Using athymic mice, research has shown that these intestinal mast cells are thymus-dependent. 1y,26 Since proliferation of globule leukocytes has been demonstrated to be thymus-independent,18s20 intestinal mast cell origin seems unlikely. These and additional studies lend support to the earlier hypothesis that globule leukocytes represent a unique population of mesenchymal origin. 18,20,21,23 The function of the globule leukocyte is poorly understood. The association between globule leukocytes and parasitic infections has been well documented and recently reviewed.* Intracellular IgE has been demonstrated in intestinal globule leukocytes of rats with enteric parasites. l 6 Increased numbers of globule leukocytes have been shown to be associated with gastrointestinal parasitism in ~h e e p ,~ cats,12 dogs,13 rats,21 and mice.2o Also, some investigators have observed a rise in the number of intestinal globule leukocytes to be temporally associated with the phenomenon of nematode expulsion in both primary and challenge infection^.^^,^^ Neoplasia of globule leukocytes is evidently extremely rare. A neoplasm involving the terminal small intestines of a domestic cat has previously been reported;6 however, globule leukocyte neoplastic proliferations have not been described for other species. The purpose of the present report is to document a second case of globule leukocyte neoplasia and to provide detailed cytologic, histologic, and ultrastructural characterization of the neoplasm. Case HistoryA 7-year-old neutered female domestic cat was presented to the Purdue University Smal...

Cytomorphological and Immunological Classification of Feline Lymphomas: Clinicopathological Features of 76 Cases

“…The globule leukocyte lymphoma can be classified as low-grade lymphomas, since it is a kind of large granular lymphocyte lymphomas composed of neoplastic mature lymphoid cells, and well-differentiated lymphomas belong to low-grade in the updated Kiel classification [21,24]. The globule leukocyte is assumed to be derived from a cytotoxic T-cell or a natural killer (NK) cell because of its perfolin-like reactivity [12] and exists in lymphoid organ of alimentary tract which can be a primary locus of tumorigenesis [5,11,12,14].…”

“…One was the globule leukocyte type that was undefined in the updated Kiel classification, since it was unobserved in human lymphomas. The globule leukocyte neoplasm is a kind of large granular lymphoma [5,11,12,14], which is distinct from other lymphomas by the feature of its unique granules in the cytoplasm (Fig. 1h).…”

Immunophenotypic and Histologic Classification of 50 Cases of Feline Gastrointestinal Lymphoma

“…One of the tumors that did not stain with B-and T-cell markers had PTAH-positive cytoplasmic granules, which is supportive of LGL lineage. [13][14][15]23 However, in another study of 11 cats, LGL granules did not stain with PTAH. 49 Therefore, in this study the lack of PTAH staining in 2 tumors containing cells with eosinophilic cytoplasmic granules does not exclude an LGL lineage.…”

“…However, confirmation of an NK origin was not feasible because specific markers for feline NK cells are not available. 29 PTAH staining, which has been used in some studies for enhanced visualization of the granules in LGLs, [13][14][15]23 was performed on tissues of all 50 cases. One of the tumors that did not stain with B-and T-cell markers had PTAH-positive cytoplasmic granules, which is supportive of LGL lineage.…”

Small Intestine Large Granular Lymphoma in a Horse

“…Many of these tumors are of Bcell origin and may be associated with hypergammaglobulinemia. 2 Intestinal neoplasms of round granulated cells include globule leukocyte tumor (GLT), 7 granulated round cell tumor (GRCT), 12 and large granular lymphoma (LGL). 13,15 These neoplasms are characterized by a proliferation of cells with a lymphocyte-like nucleus and eosinophilic cytoplasmic granules.…”