INTRACYTOPLASMIC CHROMOPHOBE INCLUSION-BODIES IN AN ANAPLASTIC MENINGIOMA

Intracytoplasmic inclusion bodies are rarely found in meningiomas. A 7 4-year-old woman had an anaplastic meningioma with intracytoplasmic ch romophobe inclusion bodies (CIB) histologically. These CIB were variou s shapes, e.g. round, teardrop-like, fusiform, horseshoe-like, crescen tic and perinuclear. The size of CIB ranged from 7 to 14 mu m and the nuclei of the tumor cells with CIB were often eccentric. Most CIB were immunopositive only for vimentin, staining more intensely than surrou nding cytoplasm in a comparative study using adjacent sections stained with hematoxylin-eosin and vimentin. CIB showed loosely textured fila mentous structures which were in parallel and entangled arrangements u ltrastructurally. The diameter of the filaments was 13-14 nm and they were thicker than normal intermediate filaments. Moreover, these filam ents appeared to be studded with granular and fuzzy substances. These findings suggest that CIB are mainly composed of abnormally synthesize d and arranged vimentin filaments.