This 17 year old pony with weight loss and diarrhea had a marked lymphocytosis (55,000/uL) and a mild anemia (30%). The lymphocytes were small to intermediate cells with clumped chromatin, indicating a mature cell neoplasm, either a primary chronic lymphocytic leukemia or a leukemic phase of a small-intermediate cell lymphoma. The tumor was suspected to be infiltrating the intestine, causing the associated clinical signs (modified Wright’s stain, 100x objective).
