Leukoproliferative disorders in horses.

Leukoproliferative disorders reported in horses include lymphoma, lymphocytic leukemia, plasma cell myeloma, granulocytic leukemia, monocytic leukemia, myelomonocytic leukemia, and eosinophilic leukemia. Lymphoma affects horses of all ages, whereas leukemias often occur in younger horses. Clinical signs are often nonspecific including depression, anorexia, fever, and weight loss. Specialized diagnostic techniques such as cytochemistry and immunophenotyping better define the cellular origin of leukoproliferative disorders, which is essential for developing appropriate therapeutic protocols and rendering an accurate prognosis.