Retroperitoneal lymphatic malformations are rare benign cystic lesions of vascular origin that show lymphatic differentiation. For a broader discussion, please refer to the parental article on lymphatic malformations.
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Terminology
These malformations were formerly called lymphangiomas. This expression is out-of-date according to the 2018-classification of ISSVA 4.
Epidemiology
Only about 1% of all lymphatic malformations occur in the retroperitoneal space. Abdominal lymphatic malformations, in total estimated in ~ 5% of cases, tend to happen more frequently in the mesentery, followed by the omentum, mesocolon, and, then retroperitoneum 1,3.
Clinical presentation
They tend to be asymptomatic, incidentally detected on imaging. Rarely, they can present as a palpable mass 3.
Radiographic features
Lymphatic malformations are well-defined multilocular cystic masses with typically homogeneous fluid content. Calcifications are uncommon. Post-contrast enhancement of the cyst wall and septa may be seen 1,3,5. It is important to remember that they can cross fascial planes and involve multiple compartments 3.
Retroperitoneal lymphatic malformations tend to be large elongated lesions that traverse adjacent anatomic compartments.
Differential diagnosis
Please refer to the article on cystic retroperitoneal lesions, for a comprehensive list of differentials.