Basal cell carcinoma (incl. subtypes)

Basalioma, BCC, basal cell epithelioma, basal epithelial carcinoma, rodent ulcer, epithelioma basocellulare, ulcus terebrans.

Basal cell carcinoma (BCC) is the most common non-melanoma skin cancer in fair-skinned individuals. It is a low-grade malignant tumor with minimal metastatic potential but pronounced local invasiveness.

In Switzerland, the annual incidence is approximately 70 new cases per 100,000 inhabitants. Across Europe, incidence varies between 76 and 165 per 100,000 per year. Globally, incidence continues to rise annually (Europe: EAPC ~6–8%). BCC typically manifests after the age of 60, with higher risk in men and in patients over 80 years, where aggressive subtypes are more common. The lifetime risk in fair-skinned populations is estimated at ~30%.

Clinical types:

• Nodular
• Superficial
• Pigmented
• Sclerodermiform / morpheaform
• Destructive (ulcus terebrans)
• Fibroepithelioma type
• Polypoid
• Post-radiogenic

Histopathological types:

• Nodular (solid)
• Superficial
• Micronodular
• Infiltrative
• Sclerodermiform
• Fibroepithelioma Pinkus type
• Adenoid
• Cystic
• Metatypical
• Basosquamous BCC
   

Originates from epidermal stem cells or bulge cells of the hair follicle.
Predisposing factors: cumulative UV-B exposure, fair skin, ionizing radiation, arsenic exposure, immunosuppression, drug-induced photosensitivity, and rare genetic syndromes (Gorlin, Rombo, Bazex-Dupré-Christol), xeroderma pigmentosum, oculocutaneous albinism.

Pearly papule or plaque with arborizing vessels, sometimes ulcerated or crusted.
Variants:

• Pigmented: reddish-brown, melanocytic pattern
• Sclerodermiform: atrophic, scar-like, telangiectatic, deeply infiltrative

Arborizing vessels, shiny white structures, large blue-gray ovoid nests, leaf-like areas, wheel-spoke structures, shotgun-like dots.

History (UV exposure, genetic risk, immunosuppression), clinical and dermatoscopic findings, histological confirmation via biopsy. Risk stratification based on clinical and histological features (e.g. NCCN, EDF, EADO, Swiss guidelines).

Primarily chronically sun-exposed areas: head, face, neck, décolleté: ~80% in the head and neck region, 70% on the face. Trunk accounts for ~15%, genital involvement is rare.

Patients report slowly growing nodular or plaque-like lesions, often longstanding, sometimes with bleeding or crusting, predominantly in facial or neck areas. Frequently multiple or recurrent lesions in older individuals.

Basaloid tumor cells with hyperchromatic nuclei and scant cytoplasm. Typical features: peripheral palisading and tumor-stroma retraction clefts. Often desmoplastic stroma with mucinous stromal or cystic deposits. Immunohistochemistry is positive for BerEP4 and Bcl-2. Infiltrative and basosquamous subtypes tend to invade deeper structures and may show perineural infiltration.

Local tissue destruction, scarring, recurrences. Metastasis is exceedingly rare (<0.1%). Immunosuppressed patients have higher risk for recurrence and multiple lesions.

Excellent when diagnosed and treated early. Recurrence rates range from 40–80% within 5 years depending on subtype and treatment modality. Patients over 80 years more frequently develop high-risk subtypes with perineural involvement but similar clearance rates.

Primary prevention: Effective UV protection, avoidance of intense sun exposure, participation in skin cancer screenings (e.g. national programs in Switzerland).

Secondary prevention: Regular follow-up in patients with prior BCC: typically after the first diagnosis every 6 months in the first year, then annually.

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