Metastatic squamous cell carcinoma of the skin.

Sunlight induced squamous cell carcinoma of the skin is common and produces low incidence of metastases. Non-actinic squamous cell carcinoma, however, possesses a metastatic potential even when well differentiated. A representative case of keratinizing squamous cell carcinoma arising in a lower extremity with development of widespread metastases is discussed. The prognostic factors associated with metastasizing de novo squamous cell carcinoma of the extremity include: site of origin, duration of lesion, degree of differentiation, sex of patient, and size of the primary lesion. Organs prone to metastasis include: regional lymph nodes, liver, lungs, and bone. As skin cancers of this variety metastasize, the clinician must recognize this potential when considering therapeutic strategy.