Less common than basal cell but more likely to metastasize.
Fair complexion, chronic UV exposure, previous burn, or other scar (i.e., scar carcinoma), exposure to inorganic arsenic or ionizing radiation. Actinic keratosis is a premalignant lesion. Actinic keratoses can be treated with topic 5-fluorouracil.
Most commonly occurs as an ulcerated nodule or a superficial erosion on the skin. Variants include:
- Bowen's disease: Erythematous patch or plaque, often with scale; noninvasive; involvement limited to epidermis and epidermal appendages (i.e., SCC in situ).
- Scar carcinoma: Suggested by sudden change in previously stable scar, esp. if ulceration or nodules appear.
- Verrucous carcinoma: Most commonly on plantar aspect of foot; low-grade malignancy but may be mistaken for a common wart.
| TREATMENT | ||
Squamous Cell CarcinomaLocal excision and Mohs micrographic surgery are most common; radiation therapy in selected cases. Metastatic disease may be treated with radiation therapy or with combination biologic therapy; 13-cis-retinoic acid 1 mg/d PO plus IFN 3 million units/d SC. Chemotherapy may be used palliatively. |