[Intradiploic leptomeningeal bone cysts (author's transl)].

A temporo-occipital lepromeningeal cyst was observed in a 70-year old man; it presented as a translucency with serpigenous outline and a sclerotic margin. There was intra- and extra-cranial bulging of the calvarium. The extremely long latent period was unusual, since the original injury had occurred at the age of four years and the probable first clinical symptoms (giddiness) had manifested themselves at the age of 65 years. Since the correct diagnosis had been made at the age of 70, there was a 66 year interval. Vertebral angiography confirmed the intracranial expansion. From the history, clinical findings and extensive radiological investigations, an epidermoid or an intradiploic leptomeningeal cyst was considered in the differential diagnosis. At surgery the latter was confirmed.