Pigmented lesions should always be inspected and observed. Most pigmented areas are nothing but freckles and moles. However a potentially deadly pigmented lesion that can occur on the foot and lower extremity is Malignant Melanoma. A physician should evaluate any pigmented lesion that suddenly occurs or a pigmented lesion that starts to change its appearance. These changes are usually subtle and may consist of increased size and depth of color, onset of bleeding, seepage of clear fluid, tumor formation, ulceration and formation of satellite pigmented lesions. The color is usually not uniform but is likely to be scattered irregularity, being brown, bluish black or black. An increase in pigmentation may precede enlargement of the lesion by several months. Although any part of the body may be affected, the most frequent site is the foot, then in order of frequency, the remainder of the lower extremity, head and neck, abdomen, arms and back. Malignant melanoma may also form under the nails of the feet and hands. The thumb and big toe are more commonly affected than the other nails. Quite often the adjacent skin to the nail is ulcerated. Usually a fungal infection is suspected and antifungal treatment may be administered for months before the true nature of the lesion is discovered. A black malignant melanoma of the toe can also be mistaken for gangrene. Overall, the incidence of malignant melanoma is quite low.
