Basal Cell Carcinoma

Synonyms

Basal cell epithelioma, basalioma.

Epidemiology

Incidence in Europe: 450 to 500/100 000/year, most common skin malignancy.

Definition

Locally destructive malignant tumour derived from pluripotential epidermal stem cells, almost never metastasizes.

Aetiology & Pathogenesis

Risk factors: Skin types I and II (pale white and fair skin), UV exposure, immunosuppression, radiation, arsenic exposure/ingestion, specific genetic predisposition. Naevoid basal cell carcinoma syndrome (Gorlin-Goltz syndrome) is a genetic disease with predisposition for multiple basal cell carcinomas.

Signs & Symptoms

Pearly nodule with telangiectases, often raised border and central ulceration in superficial type (most common). Solid or nodular type. Sclerodermiform type infiltrating without sharp borders. Other types: cystic, rodent ulcer, metatypic (aggressive), pigmented.

Localisation

Face, trunk, extremities. In contrast to squamous cell carcinoma, not restricted to sun exposed area.

Classification

No precursor lesions. Typing by histology.

Laboratory & other workups

Not necessary.

Dermatopathology

Proliferation of progenitor cells in the basal layer of the epidermis and acroinfundibulum. Tumor cells invade different layers of the dermis. Peripheral palisading (darker row of cells at periphery), mitoses, single cell necrosis (apoptosis).

Course

Slowly progressing. May be locally destructive of deeper tissues.

Complications

Recurrence rate after surgery or radiotherapy up to 5% within 5 years.

Diagnosis

Depending on clinical and histological type.

Differential diagnosis

Sebaceous hyperplasia, dermal naevi , dermatofibroma, pseudolymphoma, melanoma, carcinoma in situ (Bowen disease or Paget disease), actinic keratosis, tumors of skin appendages.

Prevention & Therapy

Depends on the type, size and location. Excision of nodular and sclerodermic type because of recurrences in particular sclerosing tumours with micrographic control of margins; Radiation therapy in nodular types, cryosurgery. For superficial variants, also consider: cryosurgery, photodynamic therapy, topical 5-fluorouracil, immunomodulators (imiquimod), ablative laser with monitoring follow up. Advanced lesions: hedgehog inhibitors.

3.3.5 Basal Cell Carcinoma