[Spontaneous rupture of infected renal cyst presenting sudden onset of right flank distension: a case report].

A 21-year-old woman was referred to our hospital for sudden onset of right flank distension. Ultrasonography, abdominal CT scan and MRI revealed a giant cyst 20 x 11 x 10 cm on the right kidney. Percutaneous puncture of the lesion was performed and fluid was drained. The fluid was yellowish and puriform. Gradually, the drainage fluid creatinine concentration increased. Cystography revealed communication between the lesion and the pyelocalyceal system. The patient underwent drainage for 25 days, causing the cyst to almost fully collapse. No recurrence has been detected in the follow-up for about 1 year. This case is the 38th case of the rupture of a renal cyst reported in the Japanese literature. We reviewed 37 cases of rupture of renal cysts previously reported in Japan.