Transvaginal sonographic pattern of peritoneal inclusion cysts

Purpose: To assess the transvaginal sonographic pattern of peritoneal inclusion cysts, a common consequence of adhesions formation often related to pelvic surgery, endometriosis and pelvic inflammatory disease. Patients and methods: Twenty‐two patients (mean age: 40 years; range: 22–56 years) with surgically proved peritoneal inclusion cysts, examined by transvaginal sonography with power Doppler within 7 days before surgery were retrospectively recruited. Indication to surgery was pelvic pain (55%), an adnexal mass (50%) or abdominal discomfort and increasing abdominal girt (27%). Ten patients (45%) had been previously submitted to some form of pelvic surgery, nine (41%) had ovarian endometriosis and two patients had a positive anamnesis for pelvic inflammatory disease. Results: In 20 cases (91%), peritoneal inclusion cysts appeared as a pelvic mass close but separated from the ovary. Mean cyst diameter was 6 cm (range 3–20 cm) and the walls were irregular in 18 (82%) cases, due to invaginations of surrounding pelvic organs (bowel loops, uterus, broad ligaments …). Cystic content was anechoic in 16 (77%) and hypoechoic in 5 (23%) cases. In one case of multilocular cyst, both hypo‐ and anechoic content was seen. A mean of five septa were found inside each cyst (range 1–15): these appeared as being of 3 mm in 3 (15%), while in two cysts both thick and thin septa were present. Septa were complete in 15 patients, incomplete in one while in six cases both complete and incomplete septa were detected. Septa had a random distribution in 12 cysts with more than one septum (67%) and a spider appearance in 6 (33%) cases, departing from the ovary and reaching the opposite wall of the cyst. Echoic projections of the cystic walls were detected in 41% of the cases, usually of few millimeters in diameter. Conclusion: Peritoneal inclusion cysts show a wide range of dimensions and morphology and can mimic malignant adnexal masses as septa and solid projections are common findings. In a woman with previous pelvic surgery or a history of ovarian endometriosis, the detection of an irregularly shaped hypo/anechoic cyst, close but separated from the ovary and attached to normal pelvic organs should suggest the peritoneal nature of the mass.