Subacute sclerosing panencephalitis (SSPE), a post-measles progressive neurological disorder is still common in India because of indifferent vaccination compliance. However, the acute fulminant form of SSPE is extremely rare. An unusual case of fulminant SSPE in an 18-year-old man from south India with an ultra-short course of 19 days presenting with hemiparesis in absence of myoclonus and progressive cognitive decline, is reported. MRI showed frontal and parieto-occipital demyelination extending to nuclear areas. Antimeasles antibodies were demonstrable in CSF and serum with oligoclonal bands in CSF despite normal CSF protein and cell count. At autopsy, unlike classical SSPE, oligodendroglia containing measles viral antigen was sparse despite florid necrotizing leukoencephalitis with acute demyelination. Measles virus was isolated from the brain with hypermutation in M gene confirming the diagnosis. Phylogenetic analysis of the viral genotype indicated that it belonged to D7 genotype which is considered rare in India.