DISSEMINATED EPENDYMOMAS OF THE CENTRAL-NERVOUS-SYSTEM

Ependymomas are rare central nervous system (CNS) neoplasms that occas ionally disseminate along the neuraxis or to extraneural sites. Defini tive criteria predictive of dissemination have yet to be determined. O ne hundred forty patients with CNS ependymoma (88 primary spinal and 5 2 primary intracranial tumors) were surgically treated by the senior a uthor (F.J.E.) between 1986 and 1994. Sixteen patients (11.4%) demonst rated tumor dissemination. The disseminated group consisted of 11 (12. 5%) of 58 primary spinal and five (9.6%) of 52 primary intracranial ep endymomas. The authors retrospectively reviewed the patients with CNS ependymoma and have identified several characteristics associated with dissemination from the primary tumor site. The mean time from diagnos is to dissemination was 6.8 years. The patients with disseminated dise ase were younger (16.8 vs. 28.3 years old, p = 0.02), had fewer gross- total resections (29% vs. 68%, p = 0.015), and had tumors with higher proliferative indices (MIB-1 staining, 13.14% vs. 2.06%, p = 0.02). Hi gh-grade tumors had a mean proliferation index of 21%, versus 2.4% and 1.6% for myxopapillary and low-grade tumors, respectively (p = 0.0003 ). In contrast to previous studies, tumor histology was the most signi ficant variable for time to dissemination as determined by multivariat e analysis (p = 0.008). Myxopapillary and high-grade tumors were 3.6 a nd 5.6 times more likely to have a shorter time to dissemination than low-grade tumors. In addition, dissemination is associated with a wors e prognosis. At follow-up review, 31% of patients with disseminated di sease had died compared to 7% of patients without dissemination (p = 0 .04). It is concluded that younger patients with subtotal resections, myxopapillary or high-grade histology, and tumors with high proliferat ive indices are at substantial risk for the development of disseminate d disease during their clinical course.