Clear cell meningioma: clinical features, CT, and MR imaging findings in 23 patients.

BACKGROUND: Clear cell meningioma (CCM) is a rare meningioma, with radiologic features not well characterized in literature. The purpose of this study was to describe and characterize the clinical features and imaging findings of CCM. MATERIALS AND METHODS: The computed tomography (n = 16) and magnetic resonance (n = 23) images of 23 patients (12 men and 11 women; mean age, 34.6 years) were retrospectively reviewed. All of the patients underwent surgical resection. Follow-up was performed through clinical observations. RESULTS: Cerebellopontine angle was the most frequently presenting location (n = 10). The tumors were isointense (n = 12) or hypointense but associated with isointense (n = 7) appearance to gray matter on T1-weighted images. However, the tumors seemed to be isointense (n = 6) or isointense and hyperintense (n = 13) on T2-weighted images. On gadolinium-enhanced T1-weighted images, heterogeneous enhancement was seen in 14 lesions. Four lesions had amorphous calcifications, 18 showed peritumoral edema, 14 had cystic areas, 2 had bone hyperostosis, and 8 manifested bone destruction. On initial surgery, 17 patients underwent complete resection, whereas 5 patients underwent subtotal resection of their tumors. The operative result for the remaining patient was unknown. Follow-up was possible in 22 patients. Eleven patients had recurrence and 2 had died. CONCLUSIONS: Clear cell meningioma is a rare subtype of meningioma that occurs in younger patients and often recurs. Cerebellopontine angle is the most affected area in this series. The extent of initial surgical resection is the most important prognostic factor. In radiological studies, CCM tends to have marked heterogeneous enhancement, prominent peritumoral edema, intratumoral cystic components, and involvement of the adjacent bone.

Solitary fibrous tumors of the central nervous system: clinical features and imaging findings in 22 patients.

INTRODUCTION: Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm originating in the central nervous system (CNS), with imaging features currently not well known. The purposes were to describe and characterize clinical features and imaging findings of CNS SFT. METHODS: We retrospectively reviewed computed tomographic (CT; n = 10) and magnetic resonance (MR) images (n = 18) of 22 patients with SFT (13 males and 9 females; mean, 47.6 years) with associated clinical records. RESULTS: Each lesion was found as a solitary, well-defined mass, ranging in size from 12 to 70 mm (mean, 38 mm). The tumor shape was roundlike in 16 cases (72.7%) and irregular in 6 cases (27.2%). The cerebellopontine angle zone was the most affected area (n = 6). On precontrast CT scans, 10 cases showed predominantly hyperattenuation (n = 9) and isoattenuation (n = 1). No lesion contained calcification, and 2 cases showed bone invasions. All 18 tumors examined by MR imaging showed homogeneous hypointensive (n = 5) or isointensive (n = 7) signal intensity and heterogeneous mixed isointense and hypointense signal intensity (n = 6) on T1-weighted images, whereas most tumors were predominantly isointense (n = 13) and hypointense (n = 4) to the cortex on T2-weighted images; on postcontrast CT and MR images, enhancement was marked homogeneous (n = 10) or heterogeneous (n = 12). Fourteen tumors had thickening of the meninges adjacent to the tumor. CONCLUSIONS: Although SFT is a rare neoplasm in the CNS, it should be considered in the differential diagnosis. The most affected area is the cerebellopontine angle zone. Solitary fibrous tumor tends to have some imaging features, such as high attenuation on CT, isointense to hypointense signal intensity on MR images, and marked enhancement.