Cutaneous T-cell lymphoma in a heifer with increased serum lactate dehydrogenase activity.

A 1-year-old heifer from an enzootic bovine leukemia virus (BLV)-free breeding herd was examined for numerous cutaneous plaques on the neck, shoulder, back, perineum, and tail. Impression smears of the skin lesions contained a large population of neoplastic lymphoblastic cells. Hematologic findings included mild anemia, neutrophilia, and lymphocytosis. The serum activity of lactate dehydrogenase (LDH) was moderately increased at admission (4712 U/L), and remained increased despite normal to minimally increased activities of liver- and muscle-specific enzymes. The heifer was serologically negative for BLV. Because of declining condition and poor prognosis, the heifer was euthanized on day 37 after presentation. At necropsy and on histologic examination, epitheliotropic and folliculotropic cutaneous lymphoma, with generalized involvement of lymph nodes and spleen and infiltration of liver and kidney, was diagnosed. Immunophenotyping results (CD79-, CD3+) were consistent with a lymphoma of T-cell origin. We concluded that cutaneous T-cell lymphoma had spread to the other internal organs, and that the neoplasm likely contributed to increased serum LDH activity.