Syncytial meningioma

Meningotheliomatous meningioma is the classic syncytial meningioma (Fig. 20.46) that resembles the small clusters of meningeal cells found normally in the meninges and choroid plexus. Whorls and psammoma bodies are often sparse (see Table 20.9). Some menin-gothelial meningiomas are divided into lobules by their fibrovascular stroma. 

Transitional meningiomas are composed of syncytial and hbroblastic components, as described previously. The presence of cells intermediate in type between syncytial and fibroblastic justifies their designation. Prominent whorls, psammoma bodies, and clusters of syncytial cells make these very common meningiomas among the easiest to identify. IHC is usually not necessary for their identification (see Table 20.7). 

Psammomatous meningiomas are crowded with psammoma bodies. They are often spinal in location. This benign variant is recognized as meningioma from the finding of syncytial vimentin and EMA-positive cells between the conspicuous, concentrically laminated psammoma bodies. 

FIGURE 20.46 Meningotheliomatous meningioma. This meningioma could not be totally resected because of its location. It has a syncytial appearance and rounded nuclei. When the patient contemplated pregnancy, the tumor s hormonal receptors were assessed. It is positive for progesterone receptors (dark brown nuclei). 

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