The primary retroperitoneal cystadenoma is very rare tumor, described by Handfield-Jones in 1924 and observed almost exclusively in women1. The symptoms are usually nonspecific, hampering its differential diagnosis with other retroperitoneal masses and makes them with imaging and surgical approach for diagnosis and treatment2.
The present report is of one case of a primary benign retroperitoneal mucinous cystadenoma.
Woman 51 year old referred abdominal pain since one year ago, located on the right flank and radiating to the lumbar region, with progressive worsening. Physical examination revealed a palpable mass in the right flank, painless. Was submitted to ultrasound examination which identified a bulky abdominal cystic lesion. Computed tomography (Figures 1 and 2) revealed homogeneous retroperitoneal cystic lesion measuring 15x12, 5x5, 5 cm and medially displacing the ascending colon, suggesting the diagnosis of cystic lymphangioma. The patient underwent exploratory laparotomy (Figures 3 and 4), which identified massive retroperitoneal cystic lesion which was dissected from adjacent structures with ease, allowing complete resection. The pancreas and ovaries showed no alterations or contiguity with the injury. No complications were observed during the postoperative course. Pathological examination of the surgical specimen revealed retroperitoneal mucinous cystadenoma benign (Figures 5 and 6).
Most patients have a palpable mass, asymptomatic or accompanied by mild abdominal pain that may be associated with nonspecific gastrointestinal complaints2. The differential diagnosis must be made with cystic lymphangioma, cystic teratoma, cystic neoplasms of the pancreas and ovary. The assessed by CT or MRI identifies retroperitoneal cystic lesion, but does not define its exact nature3; so, confirmation of the diagnosis can be established only after histological examination of the surgical specimen. Thus, the surgical approach is indicated for proper evaluation of the topography and resection of the lesion.
Histologically primary retroperitoneal mucinous cystadenoma can be classified in three types: benign, borderline and malignant4. Benign, the most common, with no recurrence after surgical resection; borderline, with adjacent proliferative columnar epithelium and small malignant potential; malignant, which can be recurrent and metastatic5. It shares histological similarities with ovarian mucinous cystadenoma and can be located anywhere in the retroperitoneum without connections to the ovary. The histogenesis remains incompletely understood. However, there are two main assumptions. According to the first, as there is similarity with ovarian mucinous cystadenoma, it is possible originated from an ectopic ovarian tissue6; however, ovarian tissue was found in the cyst wall only in few cases7 and have been described in men8. The second hypothesis suggests that they originate from an invagination of multipotent mesothelial cells with subsequent mucinous metaplasia of the mesothelial cells6.
Complete surgical resection of the lesion, as well as allowing adequate diagnostic evaluation, represents the best treatment9.
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