An unusual case of hydranencephaly presenting with an anterior midline cyst, a posterior calcified mass, cerebellar hypoplasia and occlusion of the posterior cerebral arteries

Abstract

We present an unusual case of severe hydranencephaly in a term infant who presented with the following additional unique features, which were discovered on CT, MRI and MR angiography examinations: (1) occlusion of the bilateral posterior cerebral arteries, (2) absence of the occipital lobes, (3) an ovoid calcified mass sitting on the inner table of the occipital bone, (4) severe cerebellar hypoplasia, (5) a dysmorphic cystic diencephalon, (6) a large anterior midline cyst just above the cribriform plate and (7) absence of the falx. These imaging findings were confirmed at autopsy.

Hydranencephaly: A rare cause of an enlarging head size in an infant

“…Thalamus, hypothalamus and choroid plexus are preserved and cerebellum is intact. [14] The electrophysiological studies confirm the imaging findings. Prolonged survival upto 22 years has been reported in literature with significant associated morbidity.…”

“…It is thought to be caused by occlusion of bilateral internal carotid arteries in the fetal life mainly during the second trimester due to a variety of causes. [12] It is one of the recognized forms of brain malformations which is usually associated with intrauterine fetal demise and is therefore rarely seen in postnatal life. [3] It is a rare entity with a reported incidence of less than 1 per 10,000 live births.…”

“…The posterior fossa structures as well as parts of the temporal and occipital lobe supplied by posterior cerebral arteries are usually preserved. [15] However, cases with cerebellar hypoplasia and occlusion of bilateral posterior cerebral arteries have been reported. [1] This rare disorder usually occurs after ventricles have already formed; hence, the falx is preserved.…”

“…[15] However, cases with cerebellar hypoplasia and occlusion of bilateral posterior cerebral arteries have been reported. [1] This rare disorder usually occurs after ventricles have already formed; hence, the falx is preserved. Hydranencephaly is associated with various congenital anomalies, including arthrogryposis, renal aplastic dysplasia, poly-valvular heart defect, trisomy 13 and Fowler syndrome.…”

“…Most common etiologies described for hydranencephaly are occlusion of the supra-clinoid segment of bilateral internal carotid arteries,[1] or an extreme form of leukomalacia formed by confluence of multiple cystic cavities. Other etiologies include fetal hypoxia due to maternal exposure to carbon monoxide or butane gas resulting in massive tissue necrosis with cavitation and resorption of necrotized tissue and necrotizing vasculitis or local destruction of the brain tissue secondary to intrauterine infections, e.g.…”