Introduction

Alimentary T-cell lymphoma is an uncommon disease in dogs. This tumor is usually underdiagnosed because of non-specific gastrointestinal signs. The prognosis is poor due to chemotherapeutic resistance. Additionally, previous study has not been reported in Thailand.

Objectives

To investigate the clinical and pathological findings of canine alimentary lymphoma.

Methods

An 11-year old female poodle was referred to Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University with clinical signs of persistent diarrhea and vomiting. Because of inconclusive diagnosis and no response to any treatment, an exploratory laparotomy was performed. The dog died during the operation and was necropsied. Various organs were collected and fixed in 10% neutral buffered formalin for routinely histopathological examination and immunohistochemistry using antibody against CD3 and PAX5.

Results

The physical examination presented normal body temperature and heart rate, mild abdominal cramp and normal size of palpable lymph nodes. Fecal examination found cocci bacterial overgrowth. Abdominal radiography exhibited moderate ileus sign of small intestine without obvious foreign body. Ultrasonography showed hypoechoic area in the midline of abdomen. Hematological findings showed marked thrombocytopenia, marked leukocytosis with left-shifted neutrophilia, monocytosis and lymphocytosis. Blood chemistry showed hypoproteinemia, hypoalbuminemia and increased level of alkaline phosphatase (Table 1). Histopathological examination and the positive result of CD3 antibody confirmed alimentary T-cell lymphoma (Figure 1 and Figure 2).

Conclusion

Canine alimentary T-cell lymphoma is difficult to diagnose by routinely clinical examination. The confirmation of canine alimentary T-cell lymphoma was revealed in this report with the new evidence of tumor metastasis to pancreatic parenchyma.

Table 1. Complete blood count and the blood chemistry profiles of the dog

Figure 1 1a) White firm masses resembling mesenteric lymph node embedding in mesentery. Duodenum. 1b) Abundant small lymphocyte infiltration in epithelial and submucosal layers. Duodenum, HE, 20x. 1c) Diffused clusters of neoplastic lymphocyte in hepatic sinusoid. Liver, HE, 5x. 1d) Blood vessel surrounding by metastatic tumor cells. Pancreas, HE, 20x.

Figure 2 2a) Thickening duodenal wall. Duodenum, HE, 10x. 2b) CD3 positive tumor cell in duodenal wall. Duodenum, IHC, 10x. 2c) CD3 positive neoplastic lymphocytes. Mesenteric lymph node, IHC, 20x. 2d) PAX5 negative neoplastic lymphocytes. Mesenteric lymph node, IHC, 20x.