Immunohistochemistry will be done for benign tumors, but only relatively rarely, such as lipoma, if it can be clearly identified by ordinary routine pathological examination, no further immunohistochemistry is needed. For example, immunohistochemistry is not required for lipomas when the pathological diagnosis can be confirmed by general conventional pathological examination. Immunohistochemical examination is a specific method, like matching a key with a lock, to clarify the origin of the cells by immunohistochemical methods. For example, a positive CD34 test can clarify the vascular origin, so that a tumor of vascular origin can be considered; a positive SMA test is a lesion of smooth muscle origin, so that a tumor of myogenic origin can be considered; a positive CD117 test is a lesion of mesenchymal origin. Therefore, immunohistochemistry can help determine the source, i.e., benign lesions, but there are also cases that cannot be clarified by ordinary HE examination, and immunohistochemistry is still needed to help clarify the diagnosis. In addition, Ki-67 is a proliferation index, which can not help to determine what the source is, but can tell how active the lesion is, i.e., how fast the cells are growing, which is also meaningful for indicating the malignancy of the lesion, so immunohistochemistry can be used in benign lesions.