Schizencephaly and Porencephaly Due to Fetal Intracranial Hemorrhage: A Report of Two Cases

Abstract

Schizencephaly and porencephaly are extremely rare types of cortical dysplasia. Case 1: Prenatal magnetic resonance imaging (MRI) showed wide clefts in the frontal and parietal lobes bilaterally. On postnatal day 3, MRI T2-weighted images showed multiple hypointensities in the clefts and ventricular walls, suggestive of hemosiderosis secondary to intracranial hemorrhage. Case 2: Prenatal MRI showed bilateral cleft and cyst formation in the fetal cerebrum, as well as calcification and hemosiderosis indicative of past hemorrhage. T2-weighted images showed hypointensities in the same regions as the calcification, corresponding with hemosiderosis due to intracranial hemorrhage on postnatal day 10. Thus, prenatal MRI was useful for diagnosing schizencephaly and porencephaly. Schizencephaly and porencephaly were thought to be due to fetal intracranial hemorrhage, which, in the porencephaly case, may have been related to a mutation of COL4A1.

Prevalence of COL4A1 and COL4A2 mutations in severe fetal multifocal hemorrhagic and/or ischemic cerebral lesions

“…In these cases, the cerebral anomalies were frequently hemorrhagic features 6,8,12,[14][15][16] . An association between COL4A1 gene mutations and a prenatal diagnosis of porencephaly or schizencephaly, which are consequences of intracerebral bleeding, has also been reported 7,17,18 .…”

“…In these cases, the cerebral anomalies were frequently hemorrhagic features 6,8,12,[14][15][16] . An association between COL4A1 gene mutations and a prenatal diagnosis of porencephaly or schizencephaly, which are consequences of intracerebral bleeding, has also been reported 7,17,18 . Based on our experience (Case 1) 5 and data on isolated cases reported subsequently, we defined a fetal phenotype suggestive of COL4A1 mutation.…”

“…A chronological description of the cerebral insult in the context of COL4A1 mutation has been reported in the case of a fetus in which a hyperechoic lesion in one parietal lobe, considered to be an ischemic lesion, had been noted at 19 weeks, followed by observation of another hyperechoic area at the frontotemporal level, and finally the appearance at 35 weeks of a parenchymal cleft extending to the ventricular margin 24 . In two other cases of prenatal schizencephaly, MRI showed hemosiderosis in the clefts due to hemorrhage 17 . Interestingly, in 11 of our cases, multifocal ischemic‐hemorrhagic lesions and/or hemorrhagic lesions were associated with porencephaly or schizencephaly.…”

“…Schizencephaly is a cortical dysplasia characterized by clefts in the cerebral mantle. Since these clefts result from a destructive process prior to neuronal migration, they are lined with dysplastic gray matter 17,21,22 . Porencephaly is due to a post-migration insult within the cerebral mantle, resulting in a fluid-filled cavity with no gray-matter lining 23 .…”

“…Porencephaly is due to a post-migration insult within the cerebral mantle, resulting in a fluid-filled cavity with no gray-matter lining 23 . It has been suggested that these two types of lesion result from a clastic process secondary to a vascular injury 17 . A chronological description of the cerebral insult in the context of COL4A1 mutation has been reported in the case of a fetus in which a hyperechoic lesion in one parietal lobe, considered to be an ischemic lesion, had been noted at 19 weeks, followed by observation of another hyperechoic area at the frontotemporal level, and finally the appearance at 35 weeks of a parenchymal cleft extending to the ventricular margin 24 .…”