Hygroma or cystic lymphangioma is due to an obstruction of jugular lymph sac drainage to the jugular venous system. The most common localization is the posterolateral neck region. These lesions are usually multiseptated. Between 20% and 40% of affected individuals have a normal karyotype and the remainder show diverse aneuploidies and/or malformations. The differential diagnosis includes nuchal edema, meningocele, encephalocele, cervical teratoma, pseudomembranes, hemangioma and subchorial placental cyst. The incidence of cystic lymphangioma has been reported to be 1/6,000–1,775 live-newborns. The rate of aneuploidy associated with prenatally diagnosed cases are between 45% and 60% (mainly Turner and Down syndromes). Some cases are associated with other polymalformation syndromes. Fetal outcome is uncertain and differs among studies. We present the case of a fetal cystic lymphangioma that is unusual for several reasons: its huge size, the absence of any other morphological abnormalities and aneuploidies, the young age of the mother, and the normal morphological postnatal growth.