How are skin cancers diagnosed?

How are skin cancers diagnosed? In this short video, Dr Nirush Rameswaran explains the process of skin cancer diagnosis when you see a qualified doctor for a comprehensive skin examination.

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In the video, Dr Rameswaran describes the two methods through which a doctor can diagnose skin cancer. Firstly, a doctor can often confidently diagnose a skin malignancy by using dermoscopy. A dermatoscope is a small tool like a magnifying glass that allows doctors to see beneath the layers of the skin and identify changes to the cells that characterise skin cancer.

Dermoscopy is used during every full-body skin cancer examination with a trained doctor. It is the most reliable, first-line method for skin cancer diagnosis, and must be used in order for a thorough skin check to be completed. Skin cancer can not be diagnosed with the naked eye.

The other method of skin cancer diagnosis is a biopsy, in which a small tissue sample is taken from the suspicious lesion by your doctor and sent away to a pathology lab to be tested. This is often done even if your doctor has already identified the lesion with dermoscopy, as a means to confirm the doctor's diagnosis. 

Sometimes, the biopsy is enough to entirely remove the lesion without further intervention. The pathologist will be able to confirm whether the whole lesion has been removed in this way by examining the margins of healthy skin around the biopsy sample. If there are good margins of clear skin surrounding all the malignant cells, no further treatment is usually required.

3 ways a biopsy can be performed

  1. For a punch biopsy, the doctor uses a small tool to extract a tube-shaped sample of skin and some underlying tissue.
  2. A shave biopsy involves using a tool to scrape a small sample of tissue from the surface of the skin.
  3. An excision biopsy refers to the complete removal of the suspicious spot and a margin of surrounding tissue, usually through the use of a scalpel blade.