Secondary pelvic hydatid cyst of the Douglas pouch causing ureteral obstruction and acute pyelonephritis: A rare case...

Hydatid disease caused by Echinococcus granulosus primarily affects the liver and lungs. Pelvic localization is rare, and cysts in the Douglas pouch are exceptional. Urinary tract involvement through extrinsic compression leading to hydronephrosis and pyelonephritis is exceedingly uncommon.

We report a 47-year-old Tunisian male with mental retardation who presented with fever, flank pain, and dysuria. Laboratory workup revealed leukocytosis and positive urine culture for Escherichia coli. Contrast-enhanced CT showed multiple hepatic and peritoneal hydatid cysts, the largest measuring 13 × 11 cm in the liver, and a 12 × 10 cm cyst in the Douglas pouch compressing the right ectopic ureter. This caused marked uretero-pyelo-calyceal dilatation and secondary acute pyelonephritis of the right kidney. The patient was treated with intravenous antibiotics and urinary decompression by double-J stenting, followed by albendazole and elective surgery including excision of the pelvic cyst and partial pericystectomy of hepatic lesions. Postoperative recovery was uneventful, and at 6-month follow-up the patient remained asymptomatic without recurrence.

Hydatid cysts of the Douglas pouch are extremely rare and may mimic other pelvic pathologies. Involvement of the urinary tract by extrinsic compression is exceptional and can present as recurrent urinary infections or acute pyelonephritis. Imaging plays a crucial role in diagnosis, while surgery remains the mainstay of treatment, supported by antiparasitic therapy.

Hydatid cysts in the Douglas pouch should be considered in the differential diagnosis of pelvic cystic lesions in endemic regions, particularly when associated with urinary tract obstruction.