Magnetic resonance imaging characteristics with pathological correlation of cavernous malformation in cavernous sinus

To analyze extracerebral cavernous malformation located in the cavernous sinus and correlate their magnetic resonance imaging (MRI) features to pathological findings.

Nineteen patients (5 men and 14 women; mean age, 50.6 years; range, 32-71 years) with surgically verified cavernous malformations in the cavernous sinus were reviewed. MRI including T1-weighted, T2-weighted, and postcontrasted T1-weighted imaging was carried out in all instances with a 1.5-T superconductive system (Signa; General Electric Medical Systems, Milwaukee, WI).

All these lesions measured from 2.5 cm to 6 cm (average, 4.3 cm) with 13 lesions located to the right side and 6 to the left side. Magnetic resonance images showed that 18 cases were hypointense to white matter on T1-weighted images with only one case showed mixed hypointensity and hyperintensity. On T2-weighted images, 17 cases showed marked homogeneous hyperintensity, 1 case showed marked hyperintensity with some signal void structures and 1 with mixed intensity. Marked homogeneous enhancement after contrast material administration was found in 7 cases, and the remaining 12 showed marked heterogeneous enhancement. Pathologically, these lesions can be classified as type A, type B, and type C. Type A was sponge-like with intact pseudocapsule; type B was mulberry-like with the pseudocapsule incomplete or absent; and type C was composed of both mulberry-like composition and sponge-like composition. Lesions with homogeneous contrast enhancement on MRI correlated with type A pathological findings, whereas those with heterogeneous enhancement correlated with type B and type C pathological findings. Asymmetrical dumbbell-shaped masses of 13 cases involving the sellar and round masses of 6 cases with 2 protruding into the sellar were found. All of the cavernous malformations displaced the adjacent temporal lobe without adjacent brain edema. The internal carotid arteries were displaced or encased in all cases.

If a well-demarcated, homogeneous high signal intensity lesion on T2-weighted images with a dumbbell configuration involving both parasellar and sellar regions with marked heterogeneous or homogeneous enhancement is found, the diagnosis of cavernous sinus cavernous malformation should be entertained.