Lentigo maligna is one type of the earliest stage of a skin cancer called melanoma.
The word ‘melanoma’ comes from the Greek word ‘melas’, meaning black. Melanin is the dark pigment that gives the skin its natural colour and is made in the skin by pigment cells called melanocytes. After our skin is exposed to sunlight, the melanocytes make more melanin, and so the skin becomes darker.
Melanocytes may grow together in harmless groups or clusters, which are known as moles. Most people have between 10 and 50 moles and often they are darker than the surrounding skin.
Melanomas can arise in or near to a mole, but can also appear on skin that looks quite normal. They develop when the skin pigment cells (melanocytes) become cancerous and multiply in an uncontrolled way. They can then invade the skin around them and may also spread to other areas such as the lymph nodes, liver and lungs.
Lentigo maligna is a type of melanoma called ‘in situ’ melanoma. ‘In situ’ means that the cancer cells have not had the opportunity to spread anywhere else in the body. There are cancer cells in the top layer of the skin (the epidermis) but they are all contained in the area in which they began to develop. They have not started to spread or grow (‘invade’) into deeper layers of theskin. This is why some doctors call in situ cancers ‘pre-cancer’.
Lentigo maligna is a slow growing condition which can take years to develop. It appears in skin that has had a lot of sun exposure, usually the face, neck or upper arms.
Lentigo maligna can be cured with surgery. However, if the whole area is not removed completely with the appropriate surgery, some may develop into an invasive melanoma. It is therefore important to have it removed with a rim of normal skin (an adequate surgical margin). There are also preventative measures which can be taken (see below) that will further lower the risk of recurrence in the future.