Maternal Retroperitoneal Cystic Lymphangioma During Pregnancy.

Retroperitoneal cystic lymphangiomas are rare benign tumors, and their occurrence during pregnancy is exceptionally uncommon. We describe a case of a 31-year-old patient at 36 weeks of pregnancy with a large retroperitoneal tumor discovered incidentally during routine obstetric ultrasound (US). One week later, at 37 weeks of gestation, she delivered a healthy newborn via cesarean section. Although surgical excision was initially proposed, the lesion showed spontaneous dimensional reduction in the postpartum period. Given this atypical evolution, percutaneous drainage followed by sclerosis was performed. To our knowledge, this is only the second reported case of retroperitoneal cystic lymphangioma diagnosed during pregnancy successfully managed with a less invasive approach than complete surgical resection, highlighting the potential of conservative management in selected cases.