Nonfunctioning islet cell tumors are rarer than functioning neuroendocrine pancreatic tumors. Although they share certain characteristics with functioning tumors, they do not show clinical evidence of hormonal secretion. Their symptoms usually arise as a result of the effect of the mass, jaundice, weight loss, and malaise. They are more likely to be malignant than functioning tumors. They are slow growing, however, and their size and malignancy do not preclude long survival. For these reasons they warrant aggressive surgical intervention.