Retroperitoneal bronchogenic cyst: report of a case and literature review.

A large cystic mass was found in the subdiaphragmatic region of a 46-year-old woman who had complained of continuous pain in the left flank . The cyst was located in the retroperitoneum just below the diaphragm and was adhered to the diaphragmatic skeletal muscle and abdominal aorta, but was separate from the spleen, pancreas, left adrenal gland and left kidney. The surgically resected cyst measured 8 x 8 x 7 cm and was filled with protein-rich fluid, which contained amylase and embryonal proteins such as carcinoembryonic antigen, CA125 and CA19-9. Histologically, the cyst wall was composed of a fibrovascular connective tissue containing thin smooth muscle layers and mucus-secreting glands and was lined by a ciliated pseudostratified or tall columnar epithelium without dysplastic changes. Thus, a diagnosis of bronchogenic cyst, which is usually discovered in the posterior part of the mediastinum, was made. A rare case of bronchogenic cyst and a literature review is presented.