Megalencephaly is the result of a generalized increase in neuronal and glial proliferation or diminished apoptosis.
Hemimegalencephaly is unilateral megalencephaly that is isolated, part of a hemihypertrophy syndrome or the result of hamartomatous overgrowth of one cerebral hemisphere.
One case of Canavan's with megalencephaly, diffuse subcortical and periventricular white matter T2 hyperintensity in the bilateral fronto-parieto-occipital regions and also in the cerebellum.
Van der Knaap's disease or Megaloencephalic leukodystrophy with subcortical cysts has megalencephaly with early involvement of subcortical U fibres and with cyst formation.
This patient appears to have mixed megalencephaly
with both type two and three as there is both association with neurofibromatosis-1 and involvement of cerebellum.
DISCUSSION: MLC is a rare neurodegenerative disorder characterized by infantile-onset megalencephaly
, cerebral leukoencephalopathy, and delayed onset of slowly progressive neurologic dysfunction.
Echocardiography was normal, Magnetic Resonance Imaging (MRI) of orbits and brain showed the presence of Hemangioma in left temporal fossa and periorbital soft tissues with intraorbital extension and coloboma of left eye, hypoplastic left cerebellar hemisphere and left unilateral megalencephaly
with prominent sulci/cisterns.
Pathologies like infection, metabolic disorders, ischemia, or genetic defects that cause errors in any of the stages of stem cell differentiation, neuronal migration, or cortical organization form cortical anomalies such as lissencephaly, pachygyria, schizencephaly, heterotopia, polymicrogyria, and unilateral megalencephaly
. (4,5) The etiology is unclear, although a primary malformation secondary to a neuronal migrational anomaly is considered most likely.