Perineural (Tarlov) cysts mimicking adnexal masses: a report of three cases.

Perineural (Tarlov) cysts are usually incidental findings during magnetic resonance imaging (MRI) performed for low back pain. However, in a tertiary women's hospital, they may present as incidental findings on gynecological ultrasound imaging. Approximately 40,000 pelvic scans are performed annually in our department. Tarlov cysts were identified in three women between August 2007 and September 2008. In two patients (Cases 1 and 3), these cysts were initially misdiagnosed as hydrosalpinges on ultrasound examination, the latter having a differential diagnosis of an ovarian cyst. Two patients (Cases 1 and 2) were symptomatic, although Case 2 had symptoms that could not entirely be accounted for by the location of the cyst. Although asymptomatic, Case 3 underwent laparoscopy with a view to salpingectomy/cystectomy. In these patients, confirmation of Tarlov cysts was subsequently made on either computed tomography (CT) or MRI. All three patients were managed conservatively. Here we describe their clinical presentation, the appearance of the cysts on ultrasound imaging and on CT or MRI, and their eventual outcomes.