Lymphomatosis as a Cause of Abdominal Pain and Distension in Two Adult Horses.
Authors: Perry Laura R, Butler Amanda J, John Emily, Martinson Shannon, Buote Melanie, Foote Kimberley, Burton Shelley, Stoughton William B
Journal: Journal of equine veterinary science
Summary
# Lymphomatosis as a Cause of Abdominal Pain and Distension in Two Adult Horses Lymphoma in horses rarely presents as peritoneal lymphomatosis with ascites, making ante-mortem diagnosis challenging in cases of unexplained abdominal distention and colic. Perry and colleagues examined two adult horses that presented with severe abdominal pain, distension, lethargy and inappetence, achieving diagnosis through peritoneal fluid cytology before confirming via post-mortem histology and immunohistochemistry that one horse had B-cell lymphoma affecting the distal jejunum and cecum, whilst the other had T-cell lymphoma of the cecum. Both animals exhibited extensive metastatic disease with characteristic small nodules and plaque-like masses covering the peritoneal and pleural surfaces—a presentation pattern described as peritoneal lymphomatosis. Clinicians should consider lymphoma in the differential diagnosis of horses presenting with refractory colic, marked abdominal distension and ascites, particularly when peritoneal fluid cytology reveals neoplastic cells, as early recognition may inform welfare decisions and prevent prolonged suffering. This case series highlights that whilst the prognosis for peritoneal lymphomatosis remains grave, peritoneal fluid analysis offers a practical diagnostic pathway in practice settings before post-mortem investigation.
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Practical Takeaways
- •Consider lymphomatosis in differential diagnosis for horses presenting with refractory colic, abdominal distention, and ascites, particularly when accompanied by peritoneal fluid abnormalities
- •Peritoneal fluid cytology can provide ante-mortem diagnosis of lymphoma and may help guide humane treatment decisions
- •Lymphomatosis presenting as peritoneal disease carries a poor prognosis in equine patients
Key Findings
- •Two horses presented with severe abdominal distention, colic, lethargy, and decreased appetite caused by lymphoma
- •Ante-mortem diagnosis was achieved through peritoneal fluid cytology in both cases
- •Post-mortem examination confirmed one B-cell lymphoma of distal jejunum and cecum, and one T-cell lymphoma of cecum
- •Both cases showed extensive metastasis with peritoneal and pleural serosae covered in nodules and plaque-like masses consistent with lymphomatosis