Rare Skin Tumors

What are rare skin tumors?

Skin cancer is one of the most common types of cancer, even in Switzerland. Doctors distinguish between different types of skin cancer: Basal cell carcinoma (basal cell cancer, basalioma) is the most common, followed by squamous cell carcinoma (squamous cell cancer, spinalioma)—both fall under the term“white skin cancer.” In addition, there is malignant melan oma, which is considered particularly malignant and aggressive. These three types of skin cancer account for the majority of cases.

However, experts are aware of even more types of malignant skin tumors that affect only a very small number of people and are therefore grouped under the category “rare skin tumors.” They originate from different cells and tissues. Examples include:

• Cutaneous sarcomas, e.g., dermatofibrosarcoma protuberans (the most common cutaneous sarcoma), undifferentiated pleomorphic sarcoma (also known as malignant fibrous histiocytoma), atypical fibroxanthoma, angiosarcoma, leiomyosarcoma, or Kaposi’s sarcoma.
• Merkel cell carcinoma – It is thought to originate in the stem cells of the epidermis and dermis or in early B cells of the immune system. In the past, researchers assumed that Merkel cell carcinoma originated in Merkel cells, which play a role in the sense of touch.
• Liposarcoma —it originates in adipose tissue.

The symptoms of rare skin tumors are usually skin changes, but these can vary widely and affect different parts of the body. For example, this can cause discoloration and lumps to form on the skin.

Because these skin tumors are so rare, many doctors rarely encounter them in their daily practice. In addition, they are often difficult to recognize and not easy to distinguish from other skin conditions. As a result, some patients are not diagnosed until later, when the skin tumor has already progressed further. In addition, skin tumors vary in how dangerous they are—some grow slowly, while others spread rapidly and form metastases in other organs.

Treatment for rare skin tumors usually involves surgery. In doing so, doctors try to remove the malignant tumor as completely as possible. Sometimes other treatments are used as well, such as radiation therapy.

Rare Skin Tumors – Prevalence and Age

Rare skin tumors affect only a small number of people, as the name suggests. In the European Union, experts classify a condition as a rare disease if it affects no more than five out of every 10,000 people. The age range for rare skin tumors can also vary—from young to old. And, in principle, these tumors can affect people of any gender.

Some facts and figures on selected rare skin tumors:

• Dermatofibrosarcoma protuberans: This is the most common cutaneous sarcoma. On average, patients are 40 years old at the time of diagnosis. In extremely rare cases, dermatofibrosarcoma protuberans can develop even in children. The condition affects women and men at roughly the same rate.
• Undifferentiated pleomorphic sarcoma: Approximately one to nine people out of every 100,000 develop this disease. Children, adolescents, and adults can be affected equally.
• Merkel cell carcinoma: This skin tumor usually occurs in older adults, typically after the age of 70. In recent years, the number of cases has risen sharply in Europe and the United States. Researchers suspect that the cause is an infection with the so-called Merkel cell polyoma virus. Men and women are affected by Merkel cell carcinoma at roughly the same rate. Each year, this malignant tumor affects approximately 0.4 out of every 100,000 residents.
• Angiosarcoma: This tumor accounts for approximately 5 percent of cutaneous sarcomas. It usually develops in the superficial soft tissues and skin (60 percent), particularly in the head and neck region and on the scalp.
• Kaposi’s sarcoma: There are several forms—one of which is associated with HIV infection. People of any age can develop this disease.
• Liposarcoma: This tumor accounts for approximately 20 percent of all malignant soft-tissue tumors. Men aged 50 and older are particularly likely to develop the disease.

Rare Skin Tumors: Causes Vary

There are various rare skin tumors, which in turn can have different causes. Sometimes the causes and how they develop are still unknown. When it comes to cancer, there isn’t “one” single cause anyway; rather, several factors usually have to interact for cancer to develop. In addition, experts are aware of several risk factors that increase the likelihood of developing cancer. An overview of the main causes of rare skin tumors.

• Dermatofibrosarcoma protuberans: The tumor originates in the connective tissue. However, the exact cause of this type of skin cancer is not yet known. Genes probably play a role.
• Undifferentiated pleomorphic sarcoma: The cause of this disease has not yet been determined. In rare cases, malignant fibrous histiocytoma runs in families, and affected individuals can be found across different generations. Therefore, genes and heredity likely play a role.
• Merkel cell carcinoma: Experts suspect that Merkel cell carcinoma is linked to a virus—the so-called Merkel cell polyoma virus (MCPyV). In about 80 percent of all patients with this diagnosis, this virus can be detected in the tumor tissue. However, many people carry the MCPyV without developing Merkel cell carcinoma. That is probably why other risk factors are also involved. These include, for example, advanced age, past exposure to strong UV radiation, and a weakened immune system (e.g., in people with HIV or following an organ transplant). The origin of Merkel cell carcinoma is likely not the Merkel cells in the skin, but rather stem cells in the epidermis and dermis or early B cells of the immune system.
• Angiosarcoma: The causes may include long-standing lymphedema, such as in women with breast cancer following surgery. Researchers also suspect that ionizing radiation (e.g., radiation therapy for breast cancer) and genetic mutations (BRCA1 and BRCA2) may be possible causes of angiosarcoma. Other possible “precursors” may include AV fistulas (e.g., following dialysis). It is still unclear whether carcinogenic substances, UV radiation, and foreign bodies play a role in angiosarcoma. Angiosarcomas rarely develop from benign skin tumors, such as leiomyomas or neurofibromas.
• Kaposi’s sarcoma: There are various forms of Kaposi’s sarcoma with different causes. A weakened immune system (e.g., immunosuppression following a transplant) and HIV infection likely play a role. This condition is also associated with immunodeficiency.
• Liposarcomas: They are thought to develop when embryonic precursor cells of adipose tissue become malignant—not from lipomas (benign tumors).

Symptoms: Rare skin tumors cause skin changes

The symptoms of rare skin tumors depend on the type of malignant tumor present. Some skin tumors grow slowly and rarely form cancerous spread (metastases) in other organs. Others, on the other hand, are aggressive and evolve rapidly. A common feature of all rare skin tumors is skin lesions that can appear in various parts of the body. However, they are often so nonspecific that most people do not immediately think of a malignant skin tumor. There may also be other harmless skin conditions underlying this. An overview of possible symptoms of rare skin tumors.

Dermatofibrosarcoma protuberans – Symptoms

This skin tumor grows slowly over the course of years or decades and destroys the surrounding tissue. It rarely metastasizes to other organs. Typical features include asymmetrical offshoots that grow horizontally. In addition, the tumor invades deeper structures. A dermatofibrosarcoma protuberans often presents as a skin-colored, yellow, brown, or reddish, firm tumor that does not cause pain. There may be one or more tumor nodes. This type of skin cancer most commonly develops on the extremities, the trunk, the head, or the neck.

Undifferentiated pleomorphic sarcoma – Symptoms

As with other sarcomas, there are hardly any characteristic symptoms that would suggest an undifferentiated pleomorphic sarcoma. A lump often forms, which can develop into an ulcer over time. If the tumor grows slowly, it can cause pain in some cases. Malignant fibrous histiocytoma most commonly develops on the scalp, forehead, temples, and extremities.

Merkel Cell Carcinoma – Symptoms

Merkel cell carcinomas most commonly develop in the head and neck region, as well as on the arms and legs. They rarely form on the torso. Merkel cell carcinoma can be identified by the following signs:

• reddish to violet-bluish coloration
• spherical shape
• smooth and shiny surface
• coarse texture
• sometimes spots, especially on the torso
• Rarely in the late stages: ulcers (ulcerations)

Merkel cell carcinomas are often aggressive and grow rapidly. Doctors describe the characteristics of these tumors using the acronym “AEIOU”:

• A = asymptomatic/painless
• E = rapid expansion
• I = Immunocompromised patients (weakened immune system)
• O = older patients (over 50 years of age)
• U = The tumor has developed in an area of the skin exposed to UV radiation (fair skin).

Angiosarcoma – Symptoms

Angiosarcomas of the skin primarily develop in the head and neck region and on the scalp. Often, skin discoloration and changes are initially the only visible signs of angiosarcoma. As a result, this malignant skin tumor can easily be mistaken for other skin conditions, such as hives (urticaria), rosacea, or inflammatory facial dermatosis.

People with angiosarcoma often do not experience any symptoms for a long time. In most cases, those affected feel that their quality of life is impaired by bleeding or swelling in the facial area as the disease progresses. If distant metastases are already present in other organs, pain may occur. Such cancer metastases form primarily in the lymph nodes, as well as in the lungs, liver, and spleen.

Kaposi’s Sarcoma – Symptoms

Kaposi’s sarcoma can affect various parts of the body, depending on the type. If it is related to an HIV infection, the symptoms often appear on the face and on the mucous membranes of the mouth. Classic Kaposi’s sarcoma affects the lower extremities; less commonly, it affects the hands, ears, nose, or penis.

The following symptoms may indicate Kaposi’s sarcoma:

• brownish-reddish to bluish spots or lumps
• severe fluid retention (edema) and extensive swelling—often affecting entire limbs and the face
• Hemorrhages
• Tissue death (necrosis)
• bleeding ulcers

In all four forms of Kaposi’s sarcoma, most people do not experience any symptoms for a long time. They often don’t feel any discomfort until ulcers, bleeding, and swelling occur.

Liposarcoma – Symptoms

Liposarcoma usually develops on the trunk and the lower extremities. There are isolated or multiple cancerous lesions. Lumps form under the skin that do not cause any pain. They are difficult to distinguish from benign lipomas. Liposarcomas grow relatively quickly and tend to spread through the lymphatic system and the bloodstream—thereby forming metastases in other organs. Then, additional symptoms usually develop.

Rare Skin Tumors: Diagnosis at Our Clinic

The diagnosis of rare skin tumors begins with a discussion of your medical history. We’ll ask you a few questions, including:

• What symptoms are you experiencing?
• When did the symptoms first appear?
• How pronounced are they?
• Have the symptoms improved at times or have they steadily worsened?
• Do you have any known underlying medical conditions? If so: Which one, and how long has it been in effect?
• Are you taking any medications? If so: Which ones, and since when?
• Is there a history of cancer in your family?
• Have you undergone a transplant or other treatment in the past?

These and other questions help us make an initial assessment. This is usually followed by a physical examination, during which the doctor examines the skin and feels the body for any changes. A blood test is also usually part of the standard procedure, during which laboratory physicians analyze the blood test results.

Only a tissue sample (biopsy) can confirm whether a rare skin tumor is present. During the procedure, we use a fine needle to remove cells from the suspicious area. A pathologist then analyzes it. Under a microscope, benign and malignant cells can be distinguished with a high degree of certainty.

Imaging techniques, such as ultrasound (sonography), computed tomography (CT), or magnetic resonance imaging (MRI), provide further information. They show the location, size, and extent of the tumor.

In cases of cancer, we use the so-called TNM classification to characterize and stage the tumor more precisely. The subsequent treatment also depends on this. The letter T stands for tumor size, N for affected lymph nodes, and M for metastases in other organs. We can also determine how aggressive the tumor is. ” Grading ” refers to how similar cancer cells still are to healthy cells.

Rare Skin Tumors: Prevention, Early Detection, Prognosis

In many cases, the causes of rare skin tumors have not yet been thoroughly studied. That’s why it’s almost impossible to prevent it. However, there are known risk factors for some types of malignant skin tumors, such as intense UV radiation. And here’s what you can do yourself: Always make sure you use adequate sun protection and avoid frequent, prolonged sunbathing.

It is also important to have as strong an immune system as possible, one that can effectively defend against pathogens. However, if this rare skin tumor is associated with HIV infection, an organ transplant, or breast cancer treatment, preventive measures are also virtually impossible.

There are also no known specific measures for early detection in a doctor’s office. If you already have a medical condition, please have us check it regularly as part of your follow-up care. This may make it possible to detect a rare skin tumor at an early stage.

Otherwise, the general advice always applies: See your doctor as soon as possible if you notice any changes in your skin. It’s also a good idea to see a doctor if you’re experiencing other symptoms that you can’t explain.

Course and Prognosis of Rare Skin Tumors

The course and prognosis of rare skin tumors cannot be predicted in general terms. Both depend on the type of skin tumor, its size, aggressiveness, and extent of spread. Some skin tumors grow slowly and rarely metastasize to other organs. In that case, the prognosis is usually more favorable.

Other skin tumors, on the other hand, are more aggressive; they grow rapidly, spread more quickly, and form metastases in other organs. In that case, the outlook is less favorable. Your overall health, age, and other existing medical conditions also play a role in the prognosis and course of the disease.