[Retroperitoneal cystic lymphangioma].

Cystic lymphangioma (CL) is a rare benign tumour that may arise in various sites. The retroperitoneal site of CL is less frequent than the mesenteric site. It has a polymorphic clinical presentation. The authors report the case of a 60-year-old woman presenting with a mass and pain in the right iliac fossa and right flank. Clinical examination revealed a cystic mass occupying the right flank and right iliac fossa extending as far as the hypogastrium. Medical imaging was in favour of a retroperitoneal cystic mass. Surgical exploration revealed a retroperitoneal cystic mass. Histological examination concluded on retroperitoneal cystic lymphangioma. The diagnosis of CL can be suggested by imaging, either during the antenatal period or in adults, but must be confirmed by histology. The treatment of choice is surgical.