Furthermore, the former present concurrently in the middle and posterior cranial fossae
. Chronic cholesteatoma otitis media is associated with a lesser extent with exposure of the dura mater of the skull base.
Surgical importance of the morphometry of the anterior and middle cranial fossae
(b) Axial CT showing bony destruction of the middle and posterior cranial fossae
. (c, d) Postoperative CT at 3 years after the operation shows no recurrence of cholesterol granuloma.
Skull base is a very complex region having many neural and vascular connections with the cranial fossae
, paranasal sinus, orbit and the neck.
We observed by passing a probe into the bilateral and unilateral posterior condylar foramina to find where they were opening into the posterior cranial fossae
in their entire course.
A lesion of the right mastoid bone had eroded its wall and extended toward the middle and posterior cranial fossae. The macroscopic and microscopic appearance of an excised portion of the lesion established the diagnosis of mastoid fibromatosis.
Intraoperatively, a whitish, soft erosion of the right mastoid wall was found; the erosion involved the entire mastoid area and extended into the posterior and middle cranial fossae without distinct limits.
The fundamental steps involved in intracranial spread have been reported to be (1) the entrapment of the cholesteatoma in a narrow recess, (2) erosion of the bone of the dural plates, and (3) expansion of the cholesteatoma into the cranial fossae
. (1) Until now, there has been no report of an intracranial extension of a cholesteatoma that appeared on magnetic resonance imaging (MRI) as a spherical mass with two components of different intensities.