Retroperitoneal cystic tumors are uncommon. More than two thirds are malignant. Benign lesions include lipomas and ¡eiomyomas, among others. Bronchogenic cysts are congenital anomalies that result from an abnormal budding of the primitive foregut, and are most commonly found in the mediastinum. Occasionally they can be seen in the skin, subcutaneous tissue, in the pre-sternal andpericardial areas, but those located under the diaphragm are extremely rare. We report a 24 year-old female who consulted for abdominal pain. An abdominal ultrasound disclosed a retroperitoneal cystic lesion, that was confirmed with a CAT scan. The patient was operated, finding a cyst that was adhered to the pancreas. A distal pancreatectomy and cyst excision were done. The pathological examination of the lesion showed a bronchogenic cyst. The patient was discharged ten days after surgery