MUC1 and meningioma: CD13 is a helpful immunohistochemical marker for the differential diagnosis of meningiomas and their mimics, achieving in combination with epithelial membrane antigen maximal sensitivity (100%) and showing statistically relevant difference of expression in comparison with both schwannomas (p < 0.0001) and solitary fibrous tumor/hemangiopericytomas (p < 0.0001).