A skin lesion is a variation in skin colour or texture, anywhere on the body. Some skin lesions, such as moles and freckles, are present at birth, while others are acquired over time (such as warts and scars from abrasions).
Most skin lesions are harmless, but it’s important to keep an eye on them because changes over time may indicate a serious problem. For example, one pigmented lesion that can occur on the foot and lower limbs is malignant melanoma. Another cancer-causing lesion that can occur on the feet is a condition called actinic keratosis. This normally occurs as a result of exposure to the sun, and treatment usually consists of freezing the lesions (using liquid nitrogen) or excision.
Kaposi's Sarcoma is another cancerous lesion. This can develop on the soles of the feet of those with HIV or AIDS. Kaposi's Sarcoma lesions are irregular in shape and have a purplish, reddish, or bluish-black appearance. They tend to spread and form large plaques or become nodular, with a firm, rubbery appearance.