Primary Retroperitoneal Mucinous Cystadenoma

Abstract

Mucinous cystadenomas and cystadenocarcinomas of the ovary are clinically and histopathologically well-established common tumors. However, primary retroperitoneal mucinous cystic tumors are extremely rare, and although their histopathogenesis is still uncertain, several theories have been proposed. Most authors suggest that they develop through mucinous metaplasia in a preexisting mesothelium-lined cyst. An accurate preoperative diagnosis of these tumors is difficult because no effective diagnostic measures have been established. Delay in diagnosis and treatment of this tumor may be fatal for the patient because of complications such as rupture, infection, and malignant transformation. We describe the case of a 31-year-old woman with abdominal pain and a palpable mass. Computed tomography of the abdomen revealed a retroperitoneal cystic mass, which was resected successfully through laparoscopy. Histopathological examination of the resected mass confirmed the diagnosis of a primary retroperitoneal mucinous cystadenoma. The patient was discharged on postoperative day 5 without any complications.

Keywords: Mucinous cystadenoma; Retroperitoneal neoplasms.

Fig. 1. Abdominal radiograph showing a hazy mass located over the left lower side of the abdomen displacing the left-side colon medially (arrows). (A) Abdominopelvic computed tomography scan showing a well-defined homogenous hypodense mass, measuring 8.9 cm × 9.7 cm × 10 cm in size, occupying the left retroperitoneal space and abutting the descending colon with medial displacement (arrows). Axial view (B) and coronal view (C).

Fig. 2. Intraoperative findings by laparoscopy. (A) Unilocular cystic mass in the retroperitoneum (arrow). (B) No pedicle linking the mass to the digestive or gynecologic structure was detected. The left ovary was present and normal (arrow).

Fig. 3. Gross findings of the resected specimen. (A) The cystic mass measured 10 cm × 9 cm × 9 cm in size, and the external surface showed no connection to any viscera. (B) On the cut section, the cystic mass was composed of a unilocular cyst and clear mucinous fluid. (C) The stroma consisted of fibrocollagenous tissue with no ovarian components (H&E, ×40). (D) The cyst wall was lined with a single layer of mucinous epithelial cells (H&E, ×200).