Basal Cell Carcinoma

Essentials of Diagnosis

• Pearly papule, erythematous patch > 6 mm, or nonhealing ulcer, in sun-exposed areas (face, trunk, lower legs)

• History of bleeding

• Fair-skinned person with a history of sun exposure (often intense, intermittent)

General Considerations

• Most common form of cancer

• Occur on sun-exposed skin in otherwise normal fair-skinned individuals; ultraviolet light is the cause

• Can be divided into clinical and histologic subtypes, which determine both clinical behavior and treatment

  • Clinical subtypes: superficial, nodular, pigmented, and morpheaform

  • Histologic subtypes: superficial, nodular, micronodular, and infiltrative

• Morpheaform, micronodular and infiltrative basal cell carcinomas

  • Not amenable to topical therapy or electrodesiccation and curettage

  • Typically require surgical excision or Mohs micrographic surgery

• Clinicians should examine the whole skin routinely, looking for bumps, patches, and scabbed lesions

Symptoms and Signs

• Most common presentation is a papule or nodule that may have a scab or erosion

• Occasionally, the nodules have a brown-gray color or have stippled pigment (pigmented basal cell carcinoma)

• Lesions grow slowly, attaining a size of 1–2 cm or more in diameter, usually only after years of growth

• There is a waxy, "pearly" appearance, with telangiectatic vessels easily visible

• Pearly or translucent quality of the lesions is most diagnostic, a feature best appreciated if the skin is stretched

• On the back and chest and lower legs, basal cell carcinomas appear as reddish, somewhat shiny, scaly thin papules or plaques

• Morpheaform basal cell carcinomas are scar-like in appearance

• When examining the face, look at the eyelid margins and medial canthi, the nose and alar folds, the lips, and then around and behind the ears

Differential Diagnosis

• Squamous cell carcinoma

• Actinic keratosis

• Intradermal nevus

• Fibrous papule of the nose

• Seborrheic keratosis (unpigmented type)

• Sebaceous (epidermal inclusion) cyst

• Sebaceous hyperplasia

• Keratoacanthoma

• Molluscum contagiosum

• Melanoma

• Paget disease

Diagnostic Procedures

• Lesions suspected to be basal cell carcinomas should be biopsied, by shave or punch biopsy

• Biopsy confirms the diagnosis

Medications

• Imiquimod (applied topically 5 nights per week for 6–10 weeks depending on patient reaction) and 5-fluorouracil (applied topically twice daily for up to 12 weeks)

  • May be appropriate for select patients with superficial basal cell carcinomas

  • However, the treated area must be observed for evidence of complete cure

• Hedgehog pathway inhibitors (vismodegib, sonidegib) are reserved for the treatment of advanced or metastatic basal cell carcinoma or in patients with extensive tumor burden (eg, basal cell nevus syndrome)

Surgery

• Therapy is aimed at eradication with minimal cosmetic deformity, often by excision with recurrence rates of 5% or less

• The technique of three cycles of curettage and electrodesiccation depends on the skill of the operator and is not recommended for head and neck lesions

• After 4–6 weeks of healing, it leaves a broad, hypopigmented, at times hypertrophic scar

• Mohs micrographic surgery

  • Involves removal of the tumor followed by immediate frozen section histopathologic examination of margins with subsequent reexcision of tumor-positive areas and final closure of the defect

  • Gives the highest cure rates (98%) and results in least tissue loss

Therapeutic Procedures

• Radiotherapy

  • Effective and sometimes appropriate for older individuals (age > 65)

  • However, recurrent tumors after radiation therapy are more difficult to treat and may be more aggressive

  • Very expensive, so its use should be restricted to cases where other options are not available

Follow-Up

• Patients must be monitored at least yearly to detect new or recurrent lesions

Prognosis

• Most recurrences appear in the first 1–2 years

Prevention

• Sun avoidance, particularly in children, is essential to lower the incidence of new basal cell cancers

When to Refer

• If diagnosis needs to be confirmed or if biopsy is required