Dermatologists are physicians (Medical Doctors) specializing in the diagnosis and treatment of diseases and tumors of the skin and its appendages. There are medical and surgical sides to the specialty. Dermatologic surgeons practice skin cancer surgery (including Mohs' micrographic surgery), laser surgery, photodynamic therapy (PDT) and cosmetic procedures using botulinum toxin ('Botox'), soft tissue fillers, sclerotherapy and liposuction.