A cat with cutaneous lymphosarcoma and leukemia, similar to Sezary syn
drome in human beings, had initial clinical signs that included prurit
us and exfoliative dermatosis, associated with weight loss and lymphad
enopathy. Dermatopathologic findings and ultrastructural morphologic f
eatures of the circulating cells and cellular infiltrate were consiste
nt with Sezary cells. Cutaneous lymphosarcoma and leukemia should be c
onsidered in cats with chronic pruritic exfoliative dermatoses.