[Congenital cysts of the oval window (author's transl)].

A 3 year old child with recurrent pneumococcal meningitis and a congenital cyst of the oval window is presented. An aqueous middle ear effusion was found and scintigraphy demonstrated a middle ear CSF leak. Surgical exploration revealed a cyst originating from the stapes footplate. The origin of this malformation is discussed and its possible presence in recurrent mengitis is stressed.