Laminar pattern disruption in fetal incipient polymicrogyria: insights from post-mortem magnetic resonance imaging and neuropathological correlation.

Polymicrogyria is a heterogeneous cortical malformation resulting from disruption of multiple processes of cortical development, either genetically determined or acquired. To characterize early imaging and histopathological features of incipient polymicrogyria in fetuses at early gestational age and correlate radiological patterns with underlying etiopathogenic mechanisms. Four fetuses at 21 weeks' gestational age with suspected polymicrogyria on fetal magnetic resonance imaging underwent post-mortem magnetic resonance imaging (PMMRI) and detailed neuropathological examination, including immunohistochemistry (NeuN, NSE, GFAP, MBP, CD3, CD68). Imaging and histological findings were systematically compared. Distinct imaging-histopathological patterns were identified according to etiology (ischemic, infectious, genetic). Key differentiating features included symmetry of involvement, cerebral surface appearance, integrity of the pial basement membrane, laminar pattern alterations, and associated anomalies. Combined PMMRI and neuropathology enable early characterization of polymicrogyria and provide insights into its etiopathogenesis, improving differential diagnosis and genetic counseling.