Clear-cell meningiomas have a more aggressive behavior than other meni
ngioma subtypes and the cytologic features of clear-cell meningioma ha
ve nor been described. A fine-needle aspiration biopsy (FNAB) of a sac
ral clear-cell meningioma was performed in a 28-yr-old woman. This tum
or was a metastasis from a posterior fossa meningioma thar had been un
resectable, but had been present Sor 7 yr. Cytologically, clear-cell m
eningiomas have a whorled, syncytial architecture and spindled to poly
gonal, bland-appearing nuclei. In contrast to the more classic meningi
oma, the clear-cell variety has vacuolated cytoplasm. The differential
diagnosis includes a number of other neoplastic processes. Separation
of clear-cell meningioma form these other entities may be difficult b
ecause of its rather unusual cytoplasmic features and its occurrence i
n unusual sites. (C) 1998 Wiley-Liss, Inc.