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Basal-cell carcinoma, squamous-cell carcinoma, malignant melanoma


Moles (also: birthmarks) are benign lesions composed of nevus cells. They may be present at birth or arise in the course of life, appearing in different forms and distinct colors. Moles are generally harmless, however they can be altered by sunlight and environmental influences - in this case caution is particularly advised because malignant skin tumors may develop from these normally benign changes. In categorizing skin tumors, the more common "white skin cancer" types (basal-cell carcinoma and squamous-cell carcinoma) can be distinguished from the more malign "black skin cancer" (malignant melanoma).

Basal-cell and squamous-cell carcinoma are both caused mainly by long-term exposure to intense sunlight and are age-dependent - most people fall ill between the ages of 60 and 70.

Basal-cell carcinoma appears on parts of the body that are frequently exposed to UV radiation, for example the ears, nose, lips, neck or hands. Even if basel-cell carcinoma does not form metastases, it can still grow and spread widely beneath the skin. The larger the tumor, the more invasive the required treatment will be.

The precursor for squamous-cell carcinoma, the second most common type of skin cancer, is solar keratosis. If this is not detected early and removed, there is a risk that squamous-cell carcinoma will develop. Unlike basal-cell carcinoma these often metastasize to a size of over 1 cm; thereby, metastases which initially develop in the vicinity of the tumor can also grow to affect other organs.

Malignant melanoma is the most aggressive and dangerous form of skin tumor, due partly to frequent metastasis, and in contrast to "white skin cancer" may occur after only brief, intense UV exposure. In this the genetic predisposition of the person affected, and not just the sunlight itself, is of critical importance.


In skin cancer cases, the timely discovery of suspicious lesions can actually be life-saving. The first serious indication may be sudden growth of a birthmark; pain, inflammation or itching are other warning symptoms, as well as bleeding or oozing moles.

Malignant melanoma may initially look like a mole, but develops very quickly, especially when on the back, chest or extremities. It may appear flat, or knotty and sharply defined in structure, with brown, gray or blue-black coloring. It can lead to bleeding. Some of the rarer locations of malignant melanoma include the palms, soles, finger and toe phalanges. Especially dangerous are those tumors located under the nails: these can be confused with a hematoma, fungal infection or warts. Characteristic here are the blurred contours of the spots, which can be heterogeneous in their coloring.   

Initial indications of basal-cell carcinoma may be small whitish-gray papules with small blood vessels on the surface; recurring bleeding is another symptom of the disease. Common locations are the facial area, the external ear and the scalp.

Characteristic initial signs of squamous-cell carcinoma may be reddish-yellow hyperkeratosis, which is often inflamed. In advanced stages it may cause discoloration, keratinization and growths on the affected areas.

Causes and Risks

A mole is formed when pigment-forming cells - the melanocytes - appear in large numbers at one spot. Nevus cells can also cause moles or birthmarks to form. People with very light skin tend to have more moles. Crucial here are not only genetic factors, but also the amount of time the person affected spent in sunlight during childhood. DNA damage is the UV effect that triggers the development of skin cancer.

The greatest risks in the development of skin cancer include natural as well as solar UV radiation. The artificial radiation in solariums is just as damaging if not more harmful to the skin: the erroneous assumption that solariums are harmless leads to their outright abuse, particularly among young people.

 Examination and Diagnosis

In diagnosing skin tumors, various examination techniques are used. Reflected-light microscopy (e.g. dermatoscopy) is a diagnostic standard procedure employed on a daily basis in the dermatology clinic. Reflected-light microscopy is a non-invasive method for investigating skin tumors, which is used especially for early detection and diagnostic assessment of pigmented tumors. By photographically recording the incident light displayed, even small changes in pigmented skin tumors can be recognized.

In a histological examination, samples taken from skin tumors and excised tumors are investigated in the Histology Laboratory of the Department of Dermatology. Here, in addition to conventional histological examinations,  immuno-histochemical examination methods are used. Histographic or micrographic surgery is a special histological examination process to ensure tumor-free surgical preparation.

Ultrasonic methods can complement the clinical examination of skin and lymph nodes and significantly increase the quality of the information. In the Department of Dermatology, examination methods for skin and lymph nodes are offered and employed that are carefully tailored for the care of skin tumor patients.

Depending on the type of skin tumor and the tumor data, further imaging techniques using propagation diagnostics may be necessary. All methods of propagation diagnostics such as ultrasound, conventional X-ray examinations, CT, MRI, PET-CT and scintigraphic examination procedures are available through the cooperating departments of the Medical Center - University of Freiburg.


A wide range of surgical treatment methods and the technologies required for tumor surgery are offered by the experienced surgical team of the Department of Dermatology. For certain tumor sites and more extensive tumors, optimal surgical care for skin tumors is ensured through interdisciplinary coordination with the Departments of Plastic Surgery and of Oral and Maxillofacial Surgery. Surgical treatment of tumor metastases of internal organs is offered and carried out by the various organ-specific surgical departments of the Medical Center - University of Freiburg.

With non-surgical therapies, certain skin cancers and their precursors can also be treated without an operation. At the Department of Dermatology, methods of non-surgical treatment such as phototherapy, laser therapy and photodynamic therapy (PDT) are available and well-established. Others are performed in the Department of Phototherapy extracorporeal photopheresis (ECP).

In addition, both immunotherapy and various chemotherapy procedures (e.g. mono chemotherapy, combination chemotherapy) as well as the targeted tumor therapy can be initiated, conducted and monitored. Most immune- or chemotherapy can be performed as part of a day visit to Station Stühmer or as an outpatient. The regimen is determined individually, depending on the tumor data, and after extensive patient education and possibly an interdisciplinary meeting of the Tumor Board. With certain types of skin lymphoma and in rare cases also other, non-operable skin tumors, radiation therapy can be applied. Radiation therapy is carried out by the Department of Radiation Oncology; prior to this, patients' cases are discussed in interdisciplinary tumor conferences and therapeutic plans are established.

Following successful primary care, regular follow-up care allows for treatment monitoring and serves in the early detection of secondary tumors and tumor recurrence. As part of this follow-up the necessary MRI examinations are coordinated to monitor progress.

Course and Prognosis

With early detection of skin cancer, the chances of recovery are very good and can be close to 100 percent. The probability of being cured of basal-cell carcinoma is up to 95 percent. With discovery of tumors in later stages, however, the chances of recovery decrease many times.

Miscellaneous/Other comments

The Skin Cancer Center is under the umbrella of the Comprehensive Cancer Center Freiburg - CCCF, and was established as a competence center for the care of patients with malignant skin cancers. Interdisciplinary networking with its partners at the Medical Center - University of Freiburg and with established treatment partners in the region allow for optimal patient care. This includes, among other things, interdisciplinary tumor conferences in which multidisciplinary questions regarding diagnosis and treatment are discussed and coordinated. In addition the Skin Cancer Center offers, alongside guideline-compliant treatment options for skin cancer patients participating in therapeutic trials, guaranteed access to treatment options based on the latest scientific knowledge.