BL with immunohistochemistry for MYC protein. (Left) Section showing BL associated with an epithelioid granulomatous reaction. (Right) Same case stained for MYC protein; tumor cells show strong nuclear positivity, whereas epithelioid histiocytes are negative for MYC. Strong nuclear staining is typical of BL, but may be seen in some cases of DLBCL with a high proliferative rate.