Nodules may be inflammatory or tumors. Nodule refers to a palpable round-like or oval-shaped confined substantial damage, mostly located in the dermis or subcutaneous tissues, usually more than 1 cm in diameter, the etiology of which mainly includes bacteria, fungi, and parasites. Tumor is a new organism formed by the proliferation of local tissue cells under the action of various pathogenic factors. Simply speaking, tumor is an abnormal thing that grows on a normal person, the epithelial one is called cancer, and the non-epithelial one is called tumor.