Dyke-Davidoff-Masson-like syndrome in an adult cat.

Case summary: A 4-year-old cat was presented with acute onset of lateralised neurological central nervous system (CNS) signs and seizures. Haematological and serum biochemical parameters were within normal limits. Imaging diagnostics revealed severe CT and MRI abnormalities of the right brain, similar to Dyke-Davidoff-Masson syndrome (DDMS) in human medicine. This syndrome includes cerebral hemiatrophy with compensatory calvarial hyperostosis and ventriculomegaly. Such changes have previously been reported only once in a single feline case of approximately the same age. In humans, DDMS is described as an embryonic and perinatal developmental disturbance or an acquired injury in early childhood.

Relevance and novel information: This case report shows that without further imaging diagnostics, congenital disorders can be overlooked in some rare cases of adult cats with later onset of their first clinical signs.