Basal cell carcinoma

Epidemiology
- Technically the most common cancer, but it is often excluded from data due to its low mortality and morbidity
- BCC accounts for 75% of all skin cancer
- Most common skin cancer
Pathology
- Hedgehog pathway is often mutated
- Almost never metastasises, leading to low mortality and morbidity
- May cause local destruction, which may be severe if located on the face
- Types
  - Nodular BCC
  - Superficial BCC
  - Morpheaform BCC
  - Naevoid basal cell carcinoma syndrome
    - Autosomal dominant disease
    - Multiple BCC in young age
    - Bone and neurological malformations
  - +++
Risk factors
- Chronic sun exposure
- Old age
- Skin types I and II
Clinical features
- Pearly papule or nodule
- Rolled border
- Central crater of ulceration
- On sun-exposed skin
  - Usually upper lip/nose area
- Slow growing
Types
- Nodular BCC
  - Most common type
- Superficial BCC
  - On trunk
  - Flat plaque lesion
- Nevoid basal cell carcinoma syndrome
Prognosis
- Virtually never metastasizes
- Locally aggressive
Diagnosis
- Clinical, based on typical symptoms
- Definite (histological) diagnoses often made after surgical excision of suspected lesion
- Full-thickness biopsy -> histology
Treatment
- Surgery
  - Surgical excision with 5 mm safety border
  - Primary treatment is almost all cases
- Radiotherapy
  - If surgery is not an option
- Chemotherapy
  - Only topical (5-FU)
- Alternatives for superficial and small BCCs
  - Cryosurgery
  - Photodynamic therapy
  - Laser ablation
  - Topical chemotherapy
  - Topical imiquimod
- Targeted therapy
  - Vismodegib or sonidegib
    - Hedgehog pathway inhibitors
  - For metastatic BCC or BCC which recurs after surgery
Follow-up
- Physical examination at 3, 6, 12 months
- Sun protection

Squamous cell carcinoma

Merkel cell carcinoma

Non-melanoma skin cancer related to immune system dysfunction
- Higher incidence and worse prognosis in immunocompromised
- Due to Merkel cell polyomavirus
Pinkish nodule on sun-exposed areas
Treatment is surgical excision

Dermatofibrosarcoma protuberans

Rare tumour, but the most common cutaneous sarcoma
Translocation between chromosome 17 and 22
Treatment is surgical excision

Kaposi sarcoma

Caused by HHV8, immunosuppression is risk factor
Malignant tumor of endothelial cells
4 types
- Classic – in older males
- Endemic – in Africa
- Immunosuppressive therapy-related
- AIDS-related
Clinical features
- Multiple cutaneous lesions
  - Purplish macules -> patches -> papules -> plaques -> nodules
- Rapidly growing
- Initially seen on face, oral cavity or chest
- Organs can be involved
Treatment
- Classic KS -> surgery or radiotherapy
- HIV-related KS -> treatment of AIDS alone may cause cancer regression
- KS associated with non-HIV immunosuppression -> changing immunosuppressing drug alone may cause regression