CD99 and hereditary chronic pancreatitis: Although detecting the expression of CD34, bcl-2, CD99, CD31, S100, and EMA by immunohistochemical staining can be used to better differentiate SFT/HPC from meningioma and myofibroma, it is not generally effective in diagnosing SFT/HPC.[38] Han et al[39] showed that 40% of metastatic and 85% of nonmetastatic tumors had positive CD34 immunostaining.