CYSTIC MENINGIOMAS

BACKGROUND Meningiomas are generally solid tumors and are easily diagn osed by CT scans and MRI scans. Rarely are these tumors associated wit h cysts that can cause a confusion in the pre- and intraoperative diag nosis. Cysts associated with meningiomas may be intratumoral or peritu moral. METHODS The authors conducted a retrospective study of the seve nteen meningiomas, out of a total number of 232, which were associated with cysts. The cysts were classified based on their relationship to the tumor. The patients' sex, age group, location of the tumor, and pa thological type of tumor were also analyzed. RESULTS The 17 cases of c ystic meningioma formed 7.3% of the meningiomas seen between 1984 and 1993. Eleven of these were intratumoral and 6 peritumoral. One case ha d both intra- and peritumoral cysts. The tumors were found mostly in t he fourth and fifth decades of life. Histologically, all the peritumor al cysts except one were associated with meningotheliomatous meningiom as. Tumors with peritumoral cysts were more common in males. Intratumo ral cysts, more common in females, were angioblastic or meningotheliom atous on histopathology. Only one case was an anaplastic meningioma. C ONCLUSION Cysts associated with meningiomas, although uncommon, are ce rtainly not rare. The peritumoral and the intratumoral cysts form dist inct subtypes needing separate consideration. Cystic meningiomas are o nly rarely malignant.