The two most frequently encountered types of Melanoma in situ are Lentigo Maligna and superficial spreading melanoma in situ.

Melanoma in situ, or Melanocytic Intraepithilial Neoplasta (MIN) is the earliest stage of melanoma.

The melanoma cells are just in the very top layer of skin (epidermis) and haven’t yet started to spread into the surrounding skin tissue. It is referred to as Stage 0 melanoma or sometimes described as ‘pre-cancerous’.

Lentigo Maligna is a type of melanoma in situ. It usually presents as a large flat brown freckle on sun-exposed skin of the face and neck. They often grow slowly over several years and may be 1-2 cm in size. They are more common in the elderly.

Melanoma in situ can be cured and there shouldn’t be any risk of it coming back after surgery.

What happens if I do nothing?

If left untreated, melanoma in situ can continue to grow and spread both outwards and downwards through the melanoma in situ basement membrane. Once it penetrates this membrane it becomes an invasive melanoma and could potentially spread.


After diagnosis has been made by biopsy/removal, it is usual practice to have a second surgery done to ensure all the abnormal in situ melanoma cells have been removed. All skin taken away is examined by microscope to make sure there are no more melanoma cells. Provided it has been completely removed, no further treatment will be necessary. In some instances where surgery is impossible a period of monitoring may be undertaken after full discussion.


No further follow-up is needed for patients with completely excised melanoma in situ.

Skin self-examination

People who have previously been diagnosed with melanoma in situ or Lentigo Maligna are at increased risk of developing another in a different site.
It is therefore very important to examine your skin monthly.

After a while checking your skin will get easier as you become more familiar with your skin and what your moles normally look like. A good time to do this is after a bath or shower.

What to look for

Your specialist nurse or doctor will give you advice about what to look for when you ex-amine yourself. It is important to do this at least once a month because the earlier anything like this is picked up the more chance there is of curing it.

You’ll be asked to check (by looking and feeling):

  • Your scar and surrounding area
  • The lymph nodes nearby
  • Your skin from head to toe, for any new or changing moles (using the ABCDE guide):

A – Asymmetry
Melanoma (cancerous and malignant) lesions are typically irregular in shape (asymmetrical)

B – Border
Melanoma lesions often have uneven borders (ragged or notched edges)

C – Colour
Melanoma lesions often contain many shades of brown or black or may be blue, red or flesh coloured

D – Diameter
Melanoma lesions are often more than 6 millimetres in diameter (about the size of an eraser on a pencil)

E – Elevation
Melanoma lesions will feel slightly raised above the surface of the skin

Looking after your skin

With the known link between sun exposure and melanoma, the following precautions are strongly advised:

  • Cover up in sunny weather. Loose cotton clothes and sun hats are the cheapest and most effective way to reduce sun exposure.
  • Protect your skin with sun block (sun protection factor 30+). These preparations are now also available in moisturising creams and foundation make-up. Sun blocks provide maximum protection and should be applied regularly—at least every two hours. Please see your GP about obtaining sun block (SPF30 A & B) on prescription.
  • Avoid midday sun. Outdoor interests, hobbies etc. can be rescheduled to mornings and late afternoon. Enjoy the benefits of outdoor activities without putting yourself at risk.
  • Avoid the use of sunbeds to promote and maintain tans. Self tanning lotions can be used to achieve a cosmetic tan.
  • Protect the whole family. Children especially require added protection as they are often exposed to more sunshine during the summer.

Vitamin D advice

The evidence relating to the health effects of serum Vitamin D levels, sunlight exposure and Vitamin D intake remains inconclusive. Avoiding all sunlight exposure if you suffer from light sensitivity, or to reduce the risk of melanoma and other skin cancers, may be associated with Vitamin D deficiency.

Individuals avoiding all sun exposure should consider having their serum Vitamin D measured. If levels are reduced or deficient they may wish to consider taking supplementary Vitamin D3, 10-25 micrograms per day, and increasing their intake of foods high in Vitamin D such as oily fish, eggs, meat, fortified margarines and cereals. Vitamin D3 supplements are widely available from health food shops.

Useful websites

If you have any questions please do not hesitate to ask a member of the nursing or medical staff, or call the Dermatology/Skin Cancer Specialist Nurse:

Dermatology/Skin Cancer Specialist Nurses
Tel: 01935 384 906

Plastics Secretary
Tel: 01935 384 887

Dermatology Secretary
Tel: 01935 384871

If you have served in the armed forces you may be entitled to access the Armed Forces Compensation Scheme. Please call 0800 169 22 77.

Ref: 15-17-111
Review: 11/19