A strongly CD34-positive meningioma that was difficult to distinguish from a solitary fibrous tumor.

Fibrous or transitional meningioma and solitary fibrous tumor (SFT) are frequently difficult to differentiate from each other on the basis of histopathology. It is extremely unusual for a meningioma to exhibit diffuse, strongly positive immunoreactivity for cluster of differentiation 34 (CD34), and this has never been previously reported from a histopathological specimen. A patient with transitional meningioma that exhibited strongly positive for CD34, which has been regarded as characteristic of SFT and is considered to be useful for distinguishing the latter from meningioma, is reported.