A novel idiopathic superficial neocortical degeneration and atrophy in young adult dogs.

A diffuse, chronic, superficial neocortical degeneration that resulted in atrophy was detected in five 1 to 2-year-old-dogs. Presenting neurologic signs included ataxia, dysphagia, blindness, and mentation changes. Magnetic resonance imaging on brains from 2 dogs demonstrated severe bilateral cerebrocortical atrophy and enlarged lateral and third ventricles. Grossly, multifocal, bilaterally symmetrical, extensive areas of neocortical brownish discoloration associated with atrophy of gyri and sulcal widening were recorded in the dorsal and lateral cerebral hemispheres in 3 dogs. Microscopically, in all dogs there was subacute to chronic superficial neocortical degeneration affecting all cerebral lobes, ranging from loss of the molecular layer to less frequent larger and deeper cavitations of variable size. Clinical signs probably resulted from a combination of primary neocortical degeneration and secondary degeneration in the corticobulbar and corticospinal tracts. The distribution pattern of gross and histologic cerebrocortical lesions suggests that this is a novel degenerative canine cerebral disease.