Endometriosis of the Posterior Cul-De-Sac: Clinical Presentation and Findings at Transvaginal Ultrasound

OBJECTIVE. The purpose of our study was to evaluate the clinical findings and transvaginal ultrasound features of posterior cul-de-sac endometriosis. MATERIALS AND METHODS. A retrospective search of cases over a 13-year period was performed and yielded 25 patients with posterior cul-de-sac endometriosis. The diagnosis of posterior cul-de-sac endometriosis was confirmed by histology (n = 13), conventional barium enema (n = 13), colonoscopy (n = 8), CT (n = 8), MRI (n = 17), diagnostic laparoscopy (n = 14), and laparotomy (n = 13). All patients underwent transvaginal and abdominal ultrasound including power Doppler examination. Two radiologists working in consensus analyzed the clinical data and reviewed the imaging studies. RESULTS. All 25 patients presented with lower abdominal pain that was cyclic in six patients. Eleven patients were unintended childless. Rectal discomfort was mentioned by 17 patients, two of whom also reported rectal blood loss. At physical examination, eight patients had a palpable mass in the posterior cul-de-sac. Transvaginal ultrasound detected one or more hypoechoic masses in the posterior cul-de-sac in all 25 patients. All masses were solid, noncompressible, and localized on the serosal surface of the rectosigmoid with sparing of mucosa and submucosa. The lesions had a rounded or ovoid shape and a mean sagittal diameter of 37 mm with vascularity. The masses had a spiculated or tethering contour in 19 patients. Abdominal ultrasound detected thick-walled adnexal cysts in 11 patients, hydronephrosis in eight, and involvement of the ileocecal region in five. CONCLUSION. Patients with endometriosis of the posterior cul-de-sac frequently present with atypical noncyclic symptoms. The transvaginal ultrasound features characteristic of posterior cul-de-sac endometriosis are a solid, often spiculated, noncompressible mass near the posterior cul-de-sac that is localized at the serosal surface of the rectosigmoid, spares the mucosa and submucosa, and is vascular.