Lymphosarcoma and cryptococcosis in a cat.

Cryptococcosis and lymphosarcoma were diagnosed in a 3-year-old Domestic Shorthair cat. The cat was studied immunologically, and abnormal findings included absolute lymphopenia, with a low percentage of the lymphocytes having cell surface markers of normal T and B cells, decreased responsiveness to mitogens, and low immunoglobulin concentrations in serum. Necropsy revealed cryptococcal lesions in the facial area. The cortex of the left kidney was replaced by a diffuse pattern of undifferentiated large cells compatible with those of histiocytic cell type lymphosarcoma.