Radiology Resident Case of the Week
James Choi, M.D.
Peer Review Status: Review by Dr. Simon Kao pending...
Clinical Sx:
There is usually full term pregnany which often is complicated by
hydramnios. With fetal deformity, the woman's life is jepardized.
The deformed baby has retroflexion of the head, in which the face looks uptowards the "sky" . The neck is often absent and the skin is continuous from the scalp, face and chest. The abnormal and retroflexed occiput may join the vertebrae of the spine. A rachischisis often present in most cases. The cervical spine always severely deformed with formation of vertebral anomalies, such as a block or deficiencies. Vertebral anomalies affect other parts of the spine with presentation of anterior/posterior spina bifida.
Associated malformations with iniencephaly include anencephaly, enecephalocele, hydrocephaly, cyclopia, cleft lip and palate, bifid uvula, deformed ears, rachischisis,fusion or deficiency of ribs, abnormal lobation of the lungs, diaphragmatic hernia, single umbilical artery, omphalocele, situs inversus, horseshoe or polycystic kidneys, imperforate anus, clubfeet and congenital heart disease.
Etiology/Pathophysiology:
Iniencephaly is a rare malformation with the brain and the neck
(inion) having the principal anomalies. It is most common in girls
and less in boys (<10%). It is relatively common in areas where
anencephaly is frequent.
The etiology is not very well known. A teratologic experiment on rat fetus exposed to streptonigrin imitates the human findings.
Pathology:
Miscellaneous:
Imaging:
The head is tilted up and the occiput touches the posterior aspect of
the upper thoracic vertebral bodies. The cervical spine is widened
and crowded together. Only 11 ribs are visible. There is suggestion
of multiple rib fusion. There are bilateral pneumothoraces with
communication through the left hemidiaphragm causing a
pneumoperitoneum. A large homogenous mass (left lobe of the liver
and spleen better defined on autopsy) protrudes this hernia. There
is suggestion of elevated scapulae and narrowed foramen magnum.
The University of Utah Web Path: Iniencephaly, gross
DDX:
Key references:
1. Congenital Malformations: Notes and Comments, Warkany, Josef. Year Book Medical Publishers, 1971.
2. Smith's recognizable Patterns of Human malformation, Smith, David W., W.B. Saunders Company, 1988.
ACR Code:
Keywords: