Approach to the Nevi (Mole) Exam

All nevi (or moles) should be taken seriously as they may be normal or represent a cancer. Here we review the characteristics of any mole that should increase suspicion of cancer.

Introduction to the Nevi (Mole) Exam

Before you can make a diagnosis of any skin lesion, it's important to be able to accurately describe the skin lesion. The purpose of this page is to cover the fundamental knowledge you will need to do this. 

General Approach to Nevi (Mole) Exam

If screening for melanoma:

  1. Be systematic (from head to toes)
  2. If you're really doing a full body exam, don't miss these areas:
    1. Conchal bowls (inside the ears)
    2. Medial cathi (see figure)
    3. Inner gluteal cleft
    4. Parianal region
    5. Between fingers and toes



Normal Findings with Moles

While looking for abnormal lesions, you may stumble upon these normal ones.

Normal mole

Symmetric, small than 6 mm, one color. These are the hallmarks of a normal mole. See below for signs of abnormal lesions.

Seborrheic keratosis

These are common, benign skin lesions that occur more frequently with age. The are often described as "stuck-on" lesions, as if a ball small ball of gum was thrown again a wall and stuck to it. There is nothing needed to do for these lesions other than reassure your patient. (Note: patients with many of these, such as greater than 50, often all over torso can be a sign of a hidden malignancy, usually with the gastrointestinal tract. This is referred to as the sign of Leser-Trelat.)

Cherry hemangioma

A normal and very common lesion, these are caused by the proliferation of small blood vessels in the skin. There is no need for and medical intervention for these.

Abnormal Findings - ABCDE's of Melanoma

These signs should lead you to monitor skin lesions more closely or have them biopsied to diagnose melanoma.


If you were to cut a line down the middle of this lesion, both halves will NOT look like a mirror image of each other.

Border (irregular)


Multiple colors in one lesion can suggest underlying melanoma. 


Usually greater than 6mm, which is about the size of a pencil eraser. However, remember small moles do not rule out melanoma. 


This is the most important sign! If a lesion is changing (e.g. growing, new colors or change in border), you should keep a high suspicion for melanoma.




The Ugly Duckling Sign

This refers to one mole among many that sticks out and looks different ("the ugly duck") and should raise suspicion for melanoma.





















Consult the Expert

Jennifer Chen

Dr. Chen is a Clinical Assistant Professor and Dermatologist at Stanford University Hospital and Clinics.

Clinical Pearl

When you examin the skin, always get your fingers involved to palpate lesions that are harder to see. A classic example of this is the skin cancer precursor called an actinic keratosis (image below). In this lesion, you often feel it before it becomes easier to see.

Key Learning Points

  • Learn the general approach to the nevi (mole) exam
  • Learn the signs of an abnormal lesion

Related to Dermatology Exam

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