Medullary sponge disease in horseshoe kidney.

We report on a patient with a combination of medullary sponge disease and horseshoe kidney. The coexistence of two uncommon conditions of the kidney in this case obscured the clinical picture, and the patient was perhaps subjected to unnecessary invasive tests to establish the diagnosis. Medullary sponge disease occasionally will present as hematuria, and the condition should be kept in mind as a differential diagnosis since it is almost always recognizable on intravenous urography.