Lentigo maligna melanoma (LMM) | Melanoma

Lentigo maligna melanoma (LMM)

Lentigo maligna is an increase of atypical melanocytes within the epidermis. These cells have a tendency to develop into a lentigo-maligna melanoma (LMM). Lentigo maligna can grow horizontally for years – even decades – as a precancerosis.

The transition to the vertical growth phase (deep growth) and thus to lentigo-maligna melanoma is characterized by the formation of small nodules. In this area the tumor cells expand vertically in both directions. The prognosis is relatively good because of the long horizontal growth. The relative frequency of this clinical picture is 10%, with the face and back of the hand being particularly affected. The mean age of the disease is 68 years, which is significantly higher than for superficial spreading malignant melanoma (SSM) and primary nodular malignant melanoma (NMM).

Acrolentiginous malignant melanoma

(Akren = hands, feet, nose, ears; malignant = malignant; lentigines = spots, similar to freckles, but larger and darker) In this rather rare melanoma, horizontal growth comes first to the fore, later described as vertical growth with formation of blackish nodes. This disease is similar in appearance and growth to the lentigo-maligna melanoma (LMM). In dark-skinned peoples, acrolentiginous malignant melanoma (ALM) is the most common type of melanoma.

Because its localization is not always easily accessible, ALM is often diagnosed late and therefore has an unfavorable prognosis. The relative frequency of this clinical picture is 5%. The acras = body ends (hand, foot, nose, ear…) and the nail beds are particularly affected.

The average age of the disease is 63 years. The first and most important measure in the case of a malignant melanoma is its complete removal, whereby care must be taken to ensure a sufficient safety distance so that no remaining tissue, not visible at first glance, remains and leads to further growth of the melanoma. Surgical removal is only avoided in old people in a very advanced stage of malignant melanoma without any chance of recovery.

In the case of particularly large melanomas, a skin transplant may be necessary, which is possible either as an autologous donation or as a donation from a third party. In addition, the so-called sentinel lymph node, i.e. the lymph node that is the first in the lymph drainage area of the melanoma, is removed. This node is marked with the radioactive substance technetium 99 and removed through a small skin incision.

This node is then also examined to rule out metastasis. If a metastasis is detected in this sentinel lymph node, the other lymph node stations are also removed and examined. If a lymph node is already enlarged, the entire lymph node region is directly removed without first examining the sentinel lymph node.

The further therapy depends on the stage of the disease and is determined both by the tissue examination of the surgically removed melanoma and the examination for distant metastases. There are various attempts to treat malignant melanoma in addition to surgical removal: The surgical removal of the melanoma and/or a therapy with interferons remain the means of choice.

• Chemotherapy: Chemotherapy is used for already existing distant metastases.

  There is the option to perform the therapy with only one drug or to use a scheme of two or three different drugs. The combination therapy is only considered if the physical condition allows this increased stress. The combination therapy is suitable for 25-55% of the treated persons.

  When only one drug is administered, only 14-33% benefit from the therapy, although significantly fewer side effects are expected. A cure cannot be achieved with chemotherapy.

• Interferon therapy: Interferons are proteins that occur naturally in the body and are additionally given to the body during this therapy. They activate the natural killer cells in the body, which can actively destroy cancer cells.

  In addition to surgery, interferon therapy is currently an effective and approved method in the treatment of melanoma.

• Radiotherapy: Radiotherapy is used for inoperable tumors and inoperable lymph node metastases. Visible tumor remnants after surgical removal are also irradiated. In 70% of cases, the tumor can be kept under control, but even radiotherapy is not able to cure the disease.
• Vaccines: For treatment with a vaccine, cancer cells are taken from the patient, modified in the laboratory and then administered again in modified form.

  The body is supposed to destroy these modified cells and thereby better recognize and also destroy the other cancer cells in the body. So far this therapy has not led to any success.

• Antibody therapy: A new method attempts to produce targeted antibodies in the laboratory against surface proteins of tumor cells. These antibodies bind to the tumor cell and cause its degradation by the immune system.

  For malignant melanoma, the antibody Ipilimumab was found to be effective. The therapy is only effective in every sixth patient and is associated with many side effects. Therefore, this option for the treatment of melanoma can only be recommended to a limited extent.

• Mistletoe therapy: Mistletoe is a plant that is able to influence the immune system.

  This effect is to be used for tumor treatment. However, mistletoe therapy is suspected of promoting tumor growth and should therefore not be used.

• Hyperthermic limb perfusion: In this method, chemotherapeutic agents are injected in high doses into the bloodstream of one limb, which is then bound from the rest of the body during treatment. In addition, this part of the body is overheated in order to destroy cells due to the high temperature.

  The advantage is that by separating the limb from the body, a significantly higher dosage of chemotherapy can be chosen, which would normally not be tolerated by the body. Since the separation from the body’s circulation as a complication can make an amputation of the affected part of the body necessary, this method is only used very rarely and only for certain types of tumors. This therapy option is not recommended for lymph node metastases.

• Immune stimulation: The aim of immune stimulation is to stimulate the body to attack foreign cells, especially cancer cells.

  The agents Levamisol and BCG tested so far are not able to direct the body specifically towards the destruction of tumor cells. Therefore the therapy is ineffective and is not recommended.

Malignant melanoma is one of the most dangerous cancers. Melanomas are therefore malignant, rapidly metastasizing tumors that originate from melanocytes.

Melanocytes are cells of the skin that have stored the pigment melanin. Among other things, melanin causes the tanning of the skin. This tumor spreads very quickly and early via the lymphatic system (lymph) and the blood.

This fact makes it so dangerous. Other skin tumors, such as basal cell carcinoma, scatter very rarely, which makes them relatively harmless in comparison. Depending on the type of melanoma, the biological behavior of the tumors also differs.

Some metastasize more frequently than others. The course of the disease, however, is the same for all melanomas. They develop from a single cell clone, which has the predisposition to degenerate, from which the primary tumor develops.

This initially grows within the epidermis (epidermis), the so-called melanoma in situ, and later, when it has broken through the basal membrane of the skin, as an invasive melanoma.This growth is called vertical growth. The more superficially the melanoma has grown into the skin, the greater the chance of healing. People with sun-sensitive skin are more at risk than others. Red-blonde hair and a correspondingly light skin tone entail an almost five times higher risk than black hair with darker skin tone.