Skin cancer diagnosis and detection

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on June 1, 2022.


Diagnosing skin cancer usually begins with a visual examination. The Skin Cancer Foundation and the American Cancer Society recommend monthly self-examinations and annual doctor visits to screen for skin cancer. If a suspicious spot is found, the doctor will first examine the area, noting its size, shape, color and texture, as well as any bleeding or scaling. The doctor may also examine nearby lymph nodes to see whether they are enlarged. If the patient is being seen by a primary care physician, he or she may be referred to a dermatologist who can perform more specialized tests and diagnose skin cancer.

A dermatologist may use a special microscope or magnifying lens to examine any suspicious spots more closely, a process called dermatoscopy. In many cases, the skin cancer is removed in the dermatologist's office. If a dermatologist determines the skin cancer is melanoma or Merkel cell carcinoma, more aggressive treatment may be required.

Skin cancer tests

The two most common types of tests used in diagnosing skin cancer are biopsies and imaging tests.

Skin biopsy

In many cases, the care team will remove the whole growth. During this procedure, the doctor will numb the area before removing a tissue sample.

There are several different biopsy methods, but an excisional biopsy in which the doctor removes the entire growth is often sufficient to treat the skin cancer.

Other types of biopsies include a shave biopsy, in which the doctor shaves off the top layers of the lesion, and a punch biopsy, in which the doctor uses a special tool to cut a tiny round piece of the tumor, including deeper layers of the skin.

The care team may also take a biopsy of any suspicious lymph nodes to see if they contain cancer cells.

Imaging tests

Most skin cancers—especially basal cell carcinoma, the most common form of skin cancer—remain local and do not spread to distant organs. Melanoma and Merkel cell carcinoma are more prone to spread. In those cases, one of several medical imaging procedures may be used to determine whether cancer cells have metastasized to internal organs and bones. Imaging procedures include:

These imaging procedures are non-invasive and painless. If they reveal suspicious spots or metastases, a more invasive biopsy may be required.

Can a blood test detect skin cancer?

Skin cancer cannot be detected by a complete blood count or any other blood test.

Blood tests may be used following a skin cancer diagnosis to stage the disease or track the effectiveness of treatment.

Next topic: How is skin cancer treated?

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