Bilateral Pyosalpinx Causing Obstructive Hydronephrosis: A Multimodality Imaging Approach with the Emphasis on the Diffusion-weighted Magnetic Resonance Imaging.

A 40-year-old female, who was being treated for a urinary tract infection, was admitted to the hospital due to a gradually increasing left flank colic pain. An ultrasound investigation detected right-sided hydronephrosis, and a computed tomography scan additionally showed large cystic changes in both the fallopian tubes, which were compressing the ureters and thus causing hydronephrosis. Subsequently, magnetic resonance imaging was performed, which demonstrated fluid-fluid levels inside the cystic changes. The differential diagnosis included a deep pelvic endometriotic cyst and a pyosalpinx.