Abstract

The secretary meningioma is a distinct variant of meningioma that revealed characteristic light microscopic, immunohistochemical and ultrastructural features of epithelial and secretary differentiation, which was named as a distinct subtype of meningioma by Alguacil-Garcia et al in 1986. We experienced 2 cases of secretary meningioma. One was a 53-year-old female who had suffered from sudden onset of dizziness for I day. The computerized tomography revealed a sharply marginated well enhanced mass in temporal lobe. The other was a 59-year-old female who had suffered from dizziness for 8 years. The computerized tomography revealed a well demarcated lobulated mass in petrosal ridge. In both cases, multiple hyaline inclusions were scattered in the background of meningothelial meningioma. They were PAS positive, diastase resistant, stained yellow with van Gieson, and did not stain with reticulin in contrast to Psammoma bodies. The immunohistochemistry revealed positive reaction for EMA, CEA, a-FP and cytokeratin. T'he electron microscopic study revealed interdigitation with desmosomes and abundant intracellular lumina. They were lined by numerous microvilli and filled with granular material which was composed of electron dense homogenous material, me branous material, and small membrane-bound vesicles. Microvilli were filled with electron dense material identical to the material in the lumina, and some of them were interconnected with electron dense material in the lumina. It was concluded that secretary activity of the meningothelial cells and degenerated microvilli were involved in the pathogenesis of hyaline inclusions.

• Keywords: Secretory meningioma;Hyaline inclusion;Immunohistochemistry;Electron microscopy;