[Spontaneous pyeloduodenal fistula: a case report].

A 71-year-old female presented with recurrent episodes of right flank pain and fever for the past several years. No pathogens were detected in the urine culture. Abdominal X-ray revealed staghorn calculi of the right kidney. Computerized tomography revealed pneumopelvis and staghorn stones of the right kidney. A nephrectomy was indicated based on the results of intravenous pyelography (IVP) and renogram which revealed a right non-functioning kidney. The adhesion of the right kidney with the duodenum and a transverse colon was so strong that a nephrectomy, a wedge resection of the duodenum and a transverse colectomy were performed. There was a fistula between the renal pelvis and the second portion of the duodenum. The fistula was speculated to have occurred by the spontaneous rupture of the renal pelvis to the duodenum. To the best of our knowledge, this is the 15th case of spontaneous nephroduodenal fistula in Japan.