Mucin-secreting cellular ependymoma: A light and electron microscopy study

Mucin accumulation in ependymomas is thought to be limited to the myxopapil lary variant and represents an important diagnostic feature. Similarly, sig net-ring cells in ependymomas have been shown by electron microscopy to rep resent microrosette instead of mucin secretion. This study describes an inf ratentorial ependymoma largely composed of mucinous areas and signet-ring c ells. The ependymal nature of mucin-secreting cells was confirmed by ultras tructural analysis. This case widens the variable spectrum of ependymal mor phology. The value of electron microscopy in differentiating central nervou s system neoplasms showing mucous secretion is stressed.