What is the mechanism by which small, benign neoplasms arising from endocrine organs produce deleterious affects on the patient?

The cells of the gland normally produced hormones which are secreted by neoplastic cells in an appropriate and excessive fashion because of its being not responsive to normal feedback control mechanism. Therefore, there are excess blood and tissue levels of the hormones being secreted that produced the deleterious effect of the neoplasm relate to physiologic effects.