Basal cell carcinoma is the most common form. It rarely spreads, but if left untreated, can spread to underlying tissues and destroy them. It usually occurs as a small, shiny, pearly nodule that may ulcerate and crust. Squamous cell carcinoma, although rarely life- threatening, is more dangerous than basal cell carcinoma because it spreads more rapidly. It may begin as a nodule or as a red, scaly, sharply outlined patch.
Malignant melanoma is the least common, but most deadly, type of skin cancer.
It starts as a small, mole-like growth that increases in size and forms irregular borders. It may change color, ulcerate, or bleed from a slight injury. Melanoma is completely curable in its early stages, but if left untreated, spreads rapidly through the lymph system Studies at the University of Iowa show that leukemia and lymphoma occur almost 25 percent more frequently in Iowa farmers than in the general population. Agricultural causes of these concerns have not been conclusively identified, but agents of concern include nitrate, pesticides, viruses, antigenic stimulants, and various fuels, oils, and solvents. Many agricultural workers are exposed to chemicals on a daily basis.