To diagnose skin cancer your doctor will ask about your symptoms, examine you and may also ask about your medical history. Your doctor may refer you to a dermatologist(a doctor who specialises in skin conditions) to have further tests which may include taking a biopsy-a sample of your skin is taken and sent to a laboratory for testing or taking a sentinel lymph node biopsy-an investigation which can help your doctor to find out if the cancer has spread to your lymph nodes.
Attribution: BUPA