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

This unusual clinical case adds itself to the limited list of existing reports of retroperitoneal bronchogenic cysts in the international literature. It emphasizes the difficulties encountered in making a preoperative diagnosis, since these lesions can be described as both solid and cystic masses. A 69-year-old man underwent surgery to remove an expanding mass diagnosed as originating in the adrenal gland and discovered during clinical investigation for other indications. The lesion was excised only after adrenalectomy whereupon its cystic nature was revealed. Retroperitoneal bronchogenic cysts, though rare, should be considered in the differential diagnosis of retroperitoneal expanding lesions, especially in the presence of cystic tumours of the left adrenal region. This is the first case of a retroperitoneal bronchogenic cyst reported in an adult in Italy.