[A case of spontaneous rupture of infectious renal cyst with difficulty in diagnosis].

A 27-year-old gravida was referred to an other hospital complaining of left lumbago and pyrexia, and she was diagnosed with acute pyelonephritis. Left lumbago increased and magnetic resonance imaging of abdomen demonstrated a low intensity area like hematoma around the left kidney. Then the patient was transported to our hospital under the diagnosis of high-risk graviditas. She was performed cesarean section. High-grade inflammation still continued after the operation and computerized tomography revealed the increase of high density area. We performed angiography of the left kidney for hemostasis, but the tumor in the left renal upper pole revealed hypovascularity. We started medication of imipenem/cilastatin sodium (IPM/CS). Inflammation and pyrexia did not improve until we changed antibiotics from IPM/CS to amikacin sulfate. Seven days after that high density area around the left kidney disappeared and a renal cyst was recognized by computerized tomography for the first time. Finally, the current case was diagnosed as spontaneous rupture of infectious renal cyst.