Breast: Physiologic considerations in normal, benign, and neoplastic states

The breast is a modified sweat gland that is unique to the mammalian species. It is therefore also called the mammary gland. The breast is a functional part of the reproductive system, which is subject to a variety of neuroendocrine stimuli dictating specific morphology and physiology at various stages of life. An understanding of the interplay of the morphology and physiology of the breast and the many endocrine and paracrine controls is essential to study the pathophysiology and management of benign and neoplastic disorders. In the present chapter, we cover the morphological, endocrine, paracrine, and genetic aspects of the various stages of development, function, and involution of human breast tissue. Using this information, special attention is directed to its clinical application in the diagnosis and management of both benign and malignant conditions.