One of the microscopic examinations that the pathologist performs concerns the "preinvasive" (i.e. intraductal, intralobular or in situ) component of a breast cancer. If a breast lesion is "pure" in situ carcinoma, it is said to be "noninvasive" and is not a biologic threat under most situations if appropriate treatment is accomplished. For specific in situ carcinoma information, see pathology. But even when a breast tumor is invasive, examination of the preinvasive (in situ) component can provide meaningful information. In particular if there is extensive in situ carcinoma (intraductal carcinoma) accompanying an invasive carcinoma AND the in situ carcinoma is present at or near the margin (even if the invasive carcinoma has been completely removed with a negative margin) additional surgery will often be recommended.