Medical Encyclopaedia › Basal cell carcinoma (short definition)
In brief: Basal cell carcinoma (basalioma) is the most common cancer of the skin. It usually grows slowly and only very rarely forms metastases. If untreated, however, it can grow deeper and destroy skin, cartilage and bone. If detected in time, it can be treated well in the vast majority of cases.
Causes and risk factors
The most important risk factor is UV radiation, above all sun exposure accumulated over decades and repeated sunburn, especially in childhood and adolescence. Basal cell carcinomas therefore occur mainly on the face, ears, scalp, neck and shoulders. People with fair skin that burns easily, older people, those who have used sunbeds frequently, after radiotherapy, with a long-term suppressed immune system, for example after organ transplantation, and with rare hereditary syndromes are at increased risk. A basal cell carcinoma arises from cells of the basal layer of the epidermis and hair follicles; as a rule, there is no precursor as with other types of skin cancer.
How can you recognise a basal cell carcinoma?
Typical is a skin-coloured to reddish, glassy or pearly shiny nodule with fine, branched blood vessels on the surface. The edge is often slightly raised, and the centre can sink in, crust over or repeatedly bleed. Other forms are flat, reddish, slightly scaly patches that resemble eczema (superficial basal cell carcinoma), or scar-like, whitish, poorly defined indurations (morphoeic basal cell carcinoma), which are often larger than they appear. Rarely, basal cell carcinomas are pigmented and then resemble a melanoma. An area of skin that does not heal or bleeds repeatedly should be examined by a dermatologist.
Diagnosis
The dermatologist examines the area with a dermatoscope, which makes typical vascular and structural patterns visible. The diagnosis is usually confirmed by histological examination, either of a sample or of the completely removed tumour. The growth type is also determined, which is important for the choice of therapy and the risk of recurrence. Imaging is only necessary for very large or deeply growing tumours.
Treatment
- Surgery: the standard therapy is complete removal. Especially on the face and for poorly defined or recurrent tumours, micrographically controlled surgery is used: the excision margins are examined histologically without gaps, and further tissue is only removed until the tumour has been reliably excised. This spares healthy tissue.
- Superficial basal cell carcinomas: can also be treated with creams such as imiquimod or 5-fluorouracil, with photodynamic therapy or with freezing; recurrence rates are somewhat higher than after surgery.
- Radiotherapy: when surgery is not possible or not sensible, for example in older people with large tumours.
- Advanced basal cell carcinomas: tablets that inhibit the hedgehog signalling pathway, such as vismodegib or sonidegib; if these fail, immunotherapy with cemiplimab is approved. These treatments sometimes have burdensome side effects and belong in the hands of specialised centres.
Follow-up care and prevention
Anyone who has had a basal cell carcinoma has a significantly increased risk of further basal cell carcinomas and other types of skin cancer. Regular dermatological checks of the entire skin and self-examination are therefore important. In Germany, people with statutory health insurance are entitled to a skin cancer screening examination every two years from the age of 35. Prevention includes avoiding the midday sun, seeking shade, wearing clothing, a hat and sunglasses, using sunscreen in addition, consistently avoiding sunburn in children and not using sunbeds. Treatment of a basal cell carcinoma is covered by the health insurers.
Related terms in the encyclopaedia
Skin cancer, Squamous cell carcinoma, Melanoma, Actinic keratosis, Skin cancer screening, Mohs surgery, Imiquimod, Vismodegib, Photodynamic therapy
Sources
- AWMF-S2k-Leitlinie Basalzellkarzinom der Haut (Deutsche Dermatologische Gesellschaft, Arbeitsgemeinschaft Dermatologische Onkologie)
- Leitlinienprogramm Onkologie (AWMF, Deutsche Krebsgesellschaft, Deutsche Krebshilfe): S3-Leitlinie Prävention von Hautkrebs
- Gemeinsamer Bundesausschuss (G-BA): Krebsfrüherkennungs-Richtlinie – Hautkrebs-Screening
- Europäische Arzneimittel-Agentur (EMA): Erivedge (Vismodegib) – European Public Assessment Report (EPAR)
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor, dentist or pharmacist. Last updated: October 2026.