Exencephaly in a live, full term fetus
Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...
Exencephaly is a rare malformation of the neural tube with a large amount of protruding brain tissue and absence of calvarium. It is considered to be an embryological precursor of anencephaly where the facial structures and the base of the brain are always present. Most cases are stillborn. A case of Exencephaly in a live full-term fetus which succumbed after 3 hours.

A 21 yr old gravid, primipara was admitted with a history of post maturity. Ultrasound of the abdomen revealed a single live fetus with breech presentation and suspicion of anencephaly. She was given trial labour with no response. Hence an elective caesarean section was performed. Intra-operatively minimal liquor was detected and the presentation was complete breech. The female infant was 3kgs in weight and had an APGAR score of 6 to 8. The infant expired after 3 hours.

At autopsy the fetal skull vault was absent and the brain was covered by a thick membrane with visible tortuous blood vessels. Three other swellings were noted in the occipital region, one extending up to the cervical vertebrae. The fetus had a normal forehead and the eyes were protruding. The ears, oral cavity and nasal cavity were normal. No other external anomalies were seen.

Internal autopsy showed the brain and overlying tissue is covered by a highly vascular layer below which was a layer of loose connective tissue 2 to 4 cms thick [Figure 1]. When this layer was removed, two roughly symmetrical cerebral hemispheres were seen. In the cerebral cortex, the gyri were flattened, sulci were shallower and all surfaces were highly vascular. Cut sections of the cerebrum showed a single large ventricular chamber lined by numerous multilobular soft tissue masses with a vague corpus callosum like white area. The average cortical thickness of the cerebrum was 2cms. The occipital nodules also showed similar findings. All thoracic and abdominal organs were normal and well-formed. Lungs floatation test was positive.

On microscopic examination, the layer between the cortical surface and meninges was composed of loose connective tissue containing numerous tortuous vascular channels and focal nodules of dysplastic neural elements. The cerebral tissue contained scattered neurons, neuroblasts and glial elements with a thinned out layer of cortical tissue. The nodules in the occipital region showed cerebellar tissue composed of nodules of dysplastic neural elements and were also covered by a highly vascular layer. Spinal subarachnoid space also showed foci of dysplastic neural tissue.

Exencephaly is characterized by the absence of cranial cavity and scalp with a large amount of protruding brain tissue covered by a membrane, and with prominent bulging eyeballs. Exencephaly is rarely reported in human embryos. It occurs in 1 in 5 per 1000 live births, more commonly in females. It is thought to develop at 28 wks of gestation. As with anencephaly, exencephaly is also incompatible with life. Forebrain development is disrupted and all that remains is the area cerebrovascular with a flattened remnant of disorganized brain tissue admixed with ependymal, choroid plexus and meningothelial cells.

Exencephaly is a rare precursor of anencephaly in which a large amount of brain tissue is present despite the absence of the calvaria. The brain in these cases consists of a disorganized, anarchic outgrowth of nervous tissue with polymicrogyria and nodules of heterotopias. In our case all the macroscopic and microscopic findings were as described in literature, although we could not explain the persistence of exencephaly late in pregnancy and survival of the fetus for 3 hours.

Read more at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162784/figure/F2/
Dr. K●●●●K B●●●●M and 34 others like this29 shares
Like
Comment
Share
Dr. Dr R●●u
Dr. Dr R●●u Internal Medicine
Good literature but sad end to the baby.
Oct 5, 2019Like
Dr. J●i B●●●●i
Dr. J●i B●●●●i Obstetrics and Gynaecology
Created awareness of such rare abnormality.
Oct 5, 2019Like
Dr. V●●●●●●j D●●●i
Dr. V●●●●●●j D●●●i Legal Medicine
It should have been detected earlier while the fetus was in utero, so that the fate could have been less traumatic.
Oct 6, 2019Like3