## Overview Alimentary lymphosarcoma (also called alimentary lymphoma) is a malignant neoplasm of lymphocytes that primarily affects the gastrointestinal tract. It is the most common intestinal tumor in horses and tends to occur in middle-aged to older animals. Lesions may be focal, segmental, or diffuse within the intestinal wall, most often involving the small intestine. Clinical signs result from malabsorption, protein-losing enteropathy, partial obstruction, or secondary complications such as ulceration or perforation. ## Causes The cause is unknown. No consistent viral or environmental trigger has been identified in horses. The disease may arise de novo in gut-associated lymphoid tissue or represent a component of multicentric lymphoma. ## Diagnosis Chronic weight loss, intermittent colic, diarrhea, or hypoalbuminemia raise suspicion. Rectal examination may reveal thickened intestine or enlarged mesenteric lymph nodes. Abdominal ultrasound often shows thickened intestinal walls or masses. Peritoneal fluid cytology or intestinal biopsy (via laparoscopy or exploratory surgery) provides definitive diagnosis. Differentiation from inflammatory bowel disease can be challenging without histopathology. ## Treatment There is no curative treatment. Corticosteroids (prednisolone or dexamethasone) may produce temporary improvement in appetite and clinical signs, particularly with T-cell forms. Surgical resection is occasionally possible for solitary, accessible masses without regional metastasis, but most cases are multifocal or diffuse. Supportive care addresses secondary complications. ## Recovery and Prognosis Prognosis is poor to grave. Survival is typically measured in weeks to a few months after diagnosis, although occasional horses experience longer temporary remissions with corticosteroid therapy. Euthanasia is often elected when quality of life declines. ## Prevention No preventive measures are known.
chronic weight loss; intermittent colic; diarrhea or soft feces; ventral edema; poor appetite; thickened intestine or masses on rectal or ultrasound examination
## Overview Alimentary lymphosarcoma (also called alimentary lymphoma) is a malignant neoplasm of lymphocytes that primarily affects the gastrointestinal tract. It is the most common intestinal tumor in horses and tends to occur in middle-aged to older animals. Lesions may be focal, segmental, or diffuse within the intestinal wall, most often involving the small intestine. Clinical signs result from malabsorption, protein-losing enteropathy, partial obstruction, or secondary complications such as ulceration or perforation. ## Causes The cause is unknown. No consistent viral or environmental trigger has been identified in horses. The disease may arise de novo in gut-associated lymphoid tissue or represent a component of multicentric lymphoma. ## Diagnosis Chronic weight loss, intermittent colic, diarrhea, or hypoalbuminemia raise suspicion. Rectal examination may reveal thickened intestine or enlarged mesenteric lymph nodes. Abdominal ultrasound often shows thickened intestinal walls or masses. Peritoneal fluid cytology or intestinal biopsy (via laparoscopy or exploratory surgery) provides definitive diagnosis. Differentiation from inflammatory bowel disease can be challenging without histopathology. ## Treatment There is no curative treatment. Corticosteroids (prednisolone or dexamethasone) may produce temporary improvement in appetite and clinical signs, particularly with T-cell forms. Surgical resection is occasionally possible for solitary, accessible masses without regional metastasis, but most cases are multifocal or diffuse. Supportive care addresses secondary complications. ## Recovery and Prognosis Prognosis is poor to grave. Survival is typically measured in weeks to a few months after diagnosis, although occasional horses experience longer temporary remissions with corticosteroid therapy. Euthanasia is often elected when quality of life declines. ## Prevention No preventive measures are known.
chronic weight loss; intermittent colic; diarrhea or soft feces; ventral edema; poor appetite; thickened intestine or masses on rectal or ultrasound examination