A biopsy is performed when it is necessary to know what an oral lesion is. A small piece of the soft (mucosa) or hard (bone) tissue is removed and sent to the pathologist to be studied under a microscope. Evaluating the cellular structure allows a diagnosis to be made. We most commonly recommend and perform a biopsy to rule out Squamous Cell Carcinoma or oral cancer. If you have a sore that has been present in your mouth for over two weeks and has not healed, have it evaluated by a professional.