There are many kinds of cancers of the foot. Some take the form of cysts and lesions, while others are more widespread.
Malignant melanoma is a skin cancer that is curable if caught early. Although it makes up only one percent of skin cancers, malignant melanoma accounts for over 60 percent of skin cancer deaths. It is estimated that approximately 30 percent of melanomas occur in the lower extremities, and that 3 percent occur in the feet.
Neoplastic disorders, usually called tumors, are the result of abnormal growth of tissue. Both benign or malignant tumors occur in the foot.
Osteochondromas are benign bone tumors under the toenail. Osteochrondromas account for about half of all benign bone tumors in the foot, occurring mostly in children and young adults. Unless they cause irritation to the surrounding tissue, they are generally not very painful. Sometimes, they can deform the toenail and cause an ingrown toenail. In rare cases, they are removed surgically.
Giant cell tumors are benign tumors of the tendon sheath. These masses are generally found on the toes, top of the foot, or sides of the foot. They can also occur deep inside the foot. They are firm irregular masses that are typically painful.