Prenatal diagnosis of total arhinia by MRI.

Congenital arhinia is the absence of an external nose, nasal cavities and olfactory apparatus, and extremely rare. It occurs during the early gestational stage and may be a result of maldevelopment of the paired nasal placodes embryologically. Total arhinia is often associated with other craniofacial abnormalities. Early detection may be helpful for the parents and physician. However, fewer than 40 patients with arhinia have been reported so far, and most of them were diagnosed after birth. To our knowledge, this is the first case diagnosed by fetal MRI during the second trimester of pregnancy, and confirmed by pathological examination.