[CT evaluation of the primary extracranial neoplastic diseases eroding the central skull base]

To evaluate the central skull base erosion caused by primary extracranial mass lesions with CT.

Forty-nine patients (33 males and 16 females; mean, 40.2 years) suffered from the primary extracranial neoplastic diseases with middle skull base involvement were divided into two groups: group I (10 cases), primary osseous lesions of the central skull base and group II (39 cases), primary maxillofacial neoplasms. All lesions were confirmed histopathologically by surgery and biopsy.

Four invasion patterns of the central skull base were identified on CT: I. resorption of the cortical bone (30 cases), including outer cortical margin destruction in 16 cases (group II lesions) and both inner and outer laminae resorption in 14 cases (4 group I lesions and 10 groups II lesions). II. ossification and thickening of the skull base (4 group I cases, all were fibrous dysplasia) III. erosive enlargement of the ovale and rotundam foramina (9 group II cases). IV. combined sclerosis and resorption of the skull base (6 cases, 2 group I lesions and 4 group II lesions). Involvement of the intracranial structures embraced the cavernous sinus (n = 12; group II lesions), temporal lobe (n = 11; 5 group I lesions and 6 group II lesions), and pituitary (n = 2, group II lesions). CT demonstrated the following central skull base structures were eroded: greater wing of sphenoid bone (n = 34), sphenoid body (n = 22), sphenoid process (n = 23), petrous bone (n = 15), and articular fossa of the temporal bone (n = 8).

Osseous lesions originating from the central skull base have various CT manifestations. The cortical resorption of the central skull base may be regarded as a main pattern of bone erosion caused by primary maxillofacial neoplasms, and most of them have lesions involve the greater wing of sphenoid bone through the deeper maxillofacial spaces, such as the infratemporal, pterygopalatine and parapharyngeal spaces.