Not necessarily. A lesion is a general term for any abnormality or injury to tissue, which can include a variety of disorders such as wounds, sores, cysts, moles, and tumors. While certain lesions may be cancers (either malignant  or benign lesion removal), many are non-cancerous and do not offer a severe health risk. Any new lesions which is growing in size should be assessed to determine their underlying cause and proper management.