Gross pathology of a canine brain with cerebellar abiotrophy. Note the small size of the cerebellum relative to the cerebrum. In abiotrophy, the cerebellum initially develops to the normal size but degenerates after development. This is in contrast to cerebellar hypoplasia, in which the cerebellum never fully develops. These two conditions may look similar on gross pathology, but the differences in development vs degeneration are evident on histopathology.