Suspected unilateral renal dysplasia in a cat with intermittent hematuria

A 6-month-old, castrated male, Korean short-haired cat was referred with intermittent hematuria. Physical and laboratory examination including complete blood count and serum biochemistry profiles showed no specific findings. Ultrasonography revealed a cystic lesion of the mid-abdomen, which was approximately 2 × 2 cm in size. FNA cytology of cystic fluid showed numerous cholesterol crystals of varying size and shape and granulomatous inflammation. CT examination showed fluid-filled large cystic lesion in the left side of the abdomen. Taken together, this case was diagnosed as unilateral (left) renal dysplasia and cystic inflammation led by cholesterol crystallization in the left kidney.