Melanoma: a potential skin killer

There is a disease that occurs frequently on the skin, mucous membranes and internal organs. It is often considered a melanocytic nevus and ignored by people at the beginning of the disease. However, it is a highly malignant skin disease that is prone to metastasis and has a poor prognosis. This is melanoma, known as the "king of cancers."

Melanoma is a malignant tumor produced by melanocytes in the skin and other organs. It is highly malignant, metastasizes early, and has a high mortality rate. So, how does melanoma form and develop? What are its morphological characteristics, clinical manifestations, and risk factors? And how can it be prevented? Let's listen to the self-narration of a skin "melanoma cell".

You may be unfamiliar with me, so let me introduce myself first. I was originally a normal skin melanocyte, a cell with melanin or other similar pigments. It is located in the neural crest during the embryonic period of the human body, and is generally distributed in the basal layer of the epidermis after development. My function is to secrete melanin, absorb ultraviolet rays on the skin surface, and prevent the skin from being damaged by ultraviolet rays.

We are a big family in the skin, and I have many brothers and sisters. However, due to the influence of genetics, ultraviolet radiation and changes in hormone levels, my brothers and sisters and I may gather into lumps in the skin during the proliferation process, forming pigmented moles, which are the "black moles" that everyone is familiar with.

My owner loves beauty very much and has always taken good care of her skin, but what I didn't expect was that in order to make her skin whiter and more flawless, she began to use a lot of chemical cosmetics, and even used chemical corrosives to remove the moles on her skin. Over time, chemical skin pollution was caused. Under these adverse stimuli, I was forced to transform from a melanocyte to a melanoma cell, and my personality began to change drastically. Before, my brothers and sisters were tightly united in the epidermis of the skin, but now I can cross the basement membrane and set up camp in the dermis of the skin. My appearance is also very different from before. The cell volume has become larger and the shape is abnormal. It can be epithelial, spindle-shaped, balloon-like, or tumor giant cells. The arrangement of the tissue structure is also disordered, and it can be arranged in various ways such as trabecular, glandular, lamellar, and papillary.

Melanocytes and melanoma cells (self-drawn)

Skin and melanoma structure diagram (self-drawn)

My proliferation ability becomes more vigorous, which is manifested in that the original pigmented moles on the owner's skin suddenly grow rapidly, change in shape or color, and new dark brown patches or plaques appear in the parts without pigmented moles. The lesion parts are also accompanied by slight itching. But the owner still doesn't take it seriously at this time, because there are generally no obvious bleeding, itching, tenderness, ulcers and other symptoms in the early stage.

At this point, everyone must be wondering how to distinguish between ordinary moles and melanomas that have become malignant. Please let me tell you the answer. The important signs for identifying early melanoma are as follows:

First, look at the symmetry: select the center point of the mole, draw a coordinate axis on the skin, and divide the mole into four areas. These four areas of ordinary pigmented moles are basically symmetrical, while malignant melanoma often appears asymmetrical.

Second, look at the boundaries: pigmented nevi with unclear boundaries and irregular edges are more likely to become malignant.

Third, look at the color: You need to be alert to moles with uneven colors (for example, you suddenly find that some areas are gray, some areas are blue, or the base is red, and there is dilated blood vessels).

Fourth, look at the diameter: Pigmented moles with a diameter greater than 6 mm are more likely to become malignant.

Fifth, look for progression: refers to rapid enlargement in a short period of time, or the appearance of many new small moles (satellite lesions) around the original pigmented mole, or the appearance of ulcers, erosions, swelling and bleeding on the surface for no reason.

Melanoma on the sole of the foot (self-drawn)

As our tumor tissue became stronger, the lesion continued to grow and clearly protruded from the skin surface, forming ulcers and bleeding, and irregular pigmentation was visible around the tumor. At this time, we were ready to continue the expedition, but the owner still did not take any measures, so we began to carry blood and lymphatic tissue to start the next journey.

At this stage, we will enter the host's entire body through the blood circulation and lymphatic circulation, and metastasize to distant organs. Some of them also metastasize by directly invading adjacent organs. We can metastasize to the bones in the host's body, causing osteoporosis and pain; we can also metastasize to the lungs, causing shortness of breath and coughing up blood; we can also metastasize to the liver, causing symptoms such as general weakness and loss of appetite. These are all symptoms of late-stage metastasis of melanoma. When we metastasize and infiltrate rapidly, multiple organ metastases such as the brain, liver, lungs, spleen, and bones can occur at the same time. The host begins to show symptoms such as weight loss and cachexia, but when the abnormal manifestations of the body attract the owner's attention, his life has already been seriously threatened.

Melanoma liver metastasis (self-drawn)

Because of the great harm we have caused to our master, our master will try to eradicate us at all costs. Next, our master will have to face long and painful chemotherapy, radiotherapy and targeted therapy. Here, I would like to tell you a few preventive measures for melanoma to nip it in the bud:

1. Avoid exposure to sunlight and long-term use of irritating and corrosive skin cosmetics;

2. Abnormal moles should be treated in advance and properly evaluated;

3. People with a family history of melanoma or abnormal moles should self-examine their skin once a month and have a full-body examination once a year.

4. Control your alcohol intake.

Melanoma is like a killer, lurking in human skin. As a witness to this catastrophe in my body, I know the great harm that melanoma brings to humans. The terrible thing about us is that we have strong metastatic potential and deteriorate quickly. We are often found in the late stage and can only use medical means to prolong the patient's life as much as possible. To prevent melanoma, I hope everyone can learn from my story, "pay attention at all times, detect early, and treat early", develop good living habits, and improve immunity!

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Sun Yuhang, Cao Liyuan, Zhou Yi, popular science creator

Review | Feng Jun, Deputy Chief Physician, Dermatology Department, General Hospital of Datong Coal Mine Group Co., Ltd.