Two infants are described with intractable, drug-resistant seizures from birth associated
with an enlarged cerebral hemisphere.
The first died at sixteen months and demonstrated arrested head growth. Histology
of the abnormal hemisphere showed disturbed cortical architecture, and subcortical
heterotopias with multinucleate cells resembling tuberous sclerosis cells.
Continuous fitting persisted in the second infant following callosal section. Hemispherectomy
was undertaken in an attempt to preserve function of the "normal" hemisphere. Seizures
ceased and head growth velocity accelerated. The neuropathology of the excised hemisphere
is compared with the first case.
From the literature this is the first report of a favourable outcome after hemispherectomy
for hemimegalencephaly. The finding of an echodense enlarged hemisphere may allow
presumption of this diagnosis in a neonate with unilateral seizures. After CT scan
the diagnosis may be confirmed histologically providing that a precisely orientated
frontal biopsy is submitted to the neuropathologist. We suggest that very early hemispherectomy
may be the treatment of choice for this condition.
Hemimegalencephaly - Hemispherectomy - Cortical dysplasia
