• Clinical science

Basal cell carcinoma (Basalioma)

Abstract

Basal cell carcinoma (BCC), a malignant neoplasm, is the most common type of skin cancer and primarily affects individuals with light skin. Although excessive exposure to sun is the main risk factor, chemicals and genetic factors also increase the risk of developing the disease. BCC is characterized by slowly growing nodules with a classic "pearly" appearance, which tend to ulcerate during the course of disease. Surgical excision is the treatment of choice. As BCC does not metastasize, the prognosis is excellent.

Epidemiology

  • Most common malignant skin tumor
  • Incidence: 2–3 million people per year in the US
  • Sex: > (∼ 2:1)

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[4][1]

Clinical features

  • Localization
    • Areas of skin exposed to sun
      • The palms, soles of the feet, and mucous membranes are rarely affected.
      • Eyelid
      • Nose
  • Clinical appearance
    • Pearly, indurated and nodular lesion with rolled border that is usually nontender
    • Central depression (crater) with ulceration
  • Growth
    • Slowly growing over months to years
    • Very rarely metastasizes

Most basal cell carcinomas occur on areas of skin exposed to sun!

References:[1][2][5]

Subtypes and variants

There are several types of basal cell carcinoma:

References:[6][4][7]

Diagnostics

Basal cell carcinoma lesions are usually readily identifiable, but the diagnosis should always be histologically confirmed (via full-thickness biopsy done at the edge of the lesion).

  • Dermoscopy: initial clinical evaluation of suspected BCC lesions (dermoscopy cannot confirm BCC)
  • Excisional biopsy: (full-thickness biopsy or partial-thickness biopsy) first choice
    • Most accurate assessment of the histologic subtype of the tumor
  • Wedge biopsies: used to evaluate large lesions

References:[8][4]

Pathology

References:[1]

Differential diagnoses

Trichoepithelioma

  • Definition: rare, benign tumor of the hair follicle that usually occurs in younger individuals
  • Lesions:
    • Skin-colored, firm papules
    • May occur as single or multiple lesions
  • Localization: mainly nose and cheeks
  • Treatment: excision or laser ablation

Other differential diagnoses

References:[4]

The differential diagnoses listed here are not exhaustive.

Treatment

  • Standard treatment
    • Surgical excision of BCC with a safety margin of surrounding healthy tissue
    • Mohs micrographic surgery: The tumor is removed layer by layer, and each layer is examined for tumor cells. Mohs surgery is the best method for ensuring both that the tumor is completely removed and that uninvolved skin is spared.
  • Alternatives:
    • Radiotherapy
      • Indications
        • Patients who prefer radiotherapy over surgery (esp. elderly patients)
        • Large tumor or locations that are hard to reach
        • After incomplete surgical removal
    • Other options: cryosurgery, laser ablation, and topical chemotherapy with imiquimod or 5-Fluorouracil
      • Indications: small, superficial tumors

References:[1]

Prognosis

  • Excellent prognosis with surgical excision because of the low rate of metastasis

References:[1]

last updated 10/22/2018
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