Squamous Cell Carcinoma of the Skin

Key Features

Essentials of Diagnosis

• Nonhealing ulcer or warty nodule

• Skin damage due to long-term sun exposure

• Common in fair-skinned individuals and in organ transplant recipients and other immunosuppressed patients

General Considerations

• Squamous cell carcinoma (SCC) usually occurs subsequent to prolonged sun exposure on exposed parts in fair-skinned individuals who sunburn easily and tan poorly

• It may arise from an actinic keratosis

Clinical Findings

• The lesions appear as small red, conical, hard nodules that occasionally ulcerate

Diagnosis

• Diagnosis is made by biopsy

Treatment

Surgery

• Excision is the preferred treatment of SCC

• Mohs micrographic surgery is recommended for

  • High-risk lesions (lips, temples, ears, nose)

  • Recurrent tumors

  • Aggressive histologic subtypes (perineural or perivascular invasion)

  • Large lesions (> 1.0 cm face, > 2.0 cm trunk or extremities)

  • Immunosuppressed patients

  • Lesions developing within a scar

  • Tumors arising in the setting of genetic diseases

Therapeutic Procedures

• Electrodesiccation and curettage and x-ray radiation may be used for some lesions

Outcome

Follow-Up

• Follow-up must be more frequent and thorough than for basal cell carcinoma, starting at every 3 months for 1 year, then twice yearly thereafter, with careful examination of lymph nodes

• In addition, palpation of the lips is essential to detect hard or indurated areas that represent early SCC; all such cases must be biopsied

• Multiple SCCs are very common on the sun-exposed skin of organ transplant recipients because of their immunosuppressed state; the tumors begin to appear after 5 years of immunosuppression

• Other forms of immunosuppression that may also increase skin cancer risk and be associated with more aggressive skin cancer behavior

  • Allogeneic hematopoietic stem cell transplants

  • Chronic lymphocytic leukemia (and small lymphocyte lymphoma)

  • HIV/AIDS

  • Chronic iatrogenic immunosuppression

Complications

• In actinically induced SCCs, rates of metastasis are estimated from retrospective studies to be 3–7%

• SCCs of the ear, temple, lip, oral cavity, tongue, and genitalia have much higher rates of recurrence or metastasis and require special management

• Patients with multiple squamous cell carcinomas (especially > 10) have higher rates of local recurrence and nodal metastases

Prognosis

• Tumor aggressiveness correlates with lesion size, duration, location, origin, and degree of anaplasia

• Tumors of the scalp, eyelids, nose, ears, and lips invade subcutaneous tissues and have a greater risk of subclinical tumor extension

Prevention

• Sun protection and avoidance

• Nicotinamide 500 mg orally twice daily can decrease the rate of development of squamous cell carcinomas by 30% in high-risk groups