The unexpected presence of a huge cystic hygroma with thanatophoric dysplasia type I: a case report

The presence of a thin-walled, multicystic structure posterior to the fetal head and neck with an intact vertebral column is known as a cystic hygroma. Thanatophoric dysplasia is the most lethal skeletal dysplasia. Thanatophoric dysplasia (TD) is an autosomal dominant disorder with two phenotypes. TD type I is characterized by a normal shaped skull with bowed femurs and micromelia, while TD type II is characterized by straight femurs with a cloverleaf deformity of the skull and micromelia. We report here a case of thanatophoric dysplasia type I associated with cystic hygroma, this association needs further evaluation. Case history: A 30 year old woman was referred at 26 weeks of gestation because of marked polyhydramnios. Ultrasonographic examination of the fetus revealed a narrow chest, protuberant abdomen, short curved femur, normal shaped skull with accidentally cystic hygroma were present. No other anomalies were detected. We explained to the patient the nature and severity of the anomaly and the patient preferred the termination of pregnancy. Induction of abortion was done successfully. Conclusion: This case report has highlighted the association between cystic hygroma and thanatophoric dysplasia type I. To our knowledge, this is the first report in the literature reporting the association of cystic hygroma and thanatophoric dysplasia type I. We believe that this case is useful for obstetricians and pediatricians. We also highly recommend the genetic evaluation of the fetus and parents. Women Health Hospital, Assiut, Egypt