Primary and secondary skin cancers affecting the lower extremity: Tumorous leg ulcers

Skin cancer can be primary or de novo, as in the commonest of cases, those due to chronic sun exposure. Alternatively, secondary malignancies less frequently can he associated directly with benign dermatoses. These secondary cancers may be internal, as in hepatoma developing in patients with porphyria cutanea tarda, or external, as in the association of epidermodysplasia verruciformis with squamous cell carcinoma of the skin. Some of these primary and secondary neoplasms may also affect or have a tendency to involve certain regions of the body such as the lower extremity. De novo skin cancers affecting the lower extremity include: Kaposi's sarcoma, malignant melanoma, lymphoma and metastases. Secondary cutaneous malignancies that affect the legs and feet are mostly within the category of chronic ulcerative and scarifying conditions such as burn scars, frostbite, osteomyelitis, radiation dermatitis, stasis, infections, trauma, aerodermatitis chronica atrophicans, epidermolysis bullosa. and lichen planus. Other dermatoses directly related to skin cancer development on the lower limb include the KID syndrome, porokeratosis, tylosis, verrucous carcinoma, and lymphedema.