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Knowledge on pituitary tumors is rapidly advancing. Basic research is on the verge of decoding the molecular mechanisms involved in tumor genesis, while elaborate endocrinological, neuroradiological, and ophthalmological methods have dramatically improved the diagnostic accuracy. The standard treatment modalities, which include surgery, medical treatment, and radiotherapy, have been further developed and refined, and implementation of molecular markers has significantly enhanced the histopathological classification of pituitary tumors. Translational research promotes innovative treatment modalities for pituitary tumors that are not controlled by standard treatment, and health service research aims to bring about earlier diagnosis of pituitary tumors and improvements in posttreatment care of afflicted patients. Treatment of comorbidities has become an important focus of attention and quality of life has been recognized as an important benchmark for successful treatment outcome. Pituitary tumors are an example par excellence of a disease that involves multiple medical disciplines. An interdisciplinary approach is desirable at all stages of patient management, including diagnostic workup, therapeutic decision-making, treatment, and follow-up patient care. A major challenge in the management of pituitary tumors is a lack of familiarity with the issues encountered in related disciplines. The increasing complexity in the field of pituitary tumors was the impetus for conceptualizing this comprehensive and interdisciplinary textbook on pituitary tumors. Its purpose is to provide easy access to the state-of-the-art knowledge on pituitary tumors in a single source. We hope that the textbook finds interest among colleagues from all disciplines, including physicians, endocrinologists, neuro-ophthalmologists, neuroradiologists, neurosurgeons, neuropathologists, oncologists, and radiotherapists who are dedicated to the treatment of patients suffering from pituitary tumors and among researchers who are committed to scientific progress in the field of pituitary tumors. Pituitary tumors are not only an interdisciplinary, but also an interprofessional challenge. Among the professionals involved, assistance personnel play a crucial role in the care of patients with pituitary tumors and, hence, are among the target audience. Specific chapters are dedicated to topics in advanced endocrine nursing in the support of patients with pituitary tumors. Hopefully, the textbook will be helpful for educating students and trainees interested in pituitary tumors. The textbook could also serve as a comprehensive resource for those who care for patients with pituitary disease, but have limited access to specialists in neighboring disciplines. Surgical videos are essential illustrative material for neurosurgeons with an interest in pituitary surgery. Furthermore, pituitary surgeons appreciate the avid interest of colleagues from other disciplines who join transsphenoidal procedures to supplement their knowledge.Hence, we haveincluded a video chapterin the electronic version. Itillustrates the two principal techniques of transsphenoidal pituitary surgery, endoscopy and microscopy, and shows both standard and extended approaches, as well as examples of removal of various pituitary tumor entities. The springboard for the project was the Pituitary Working Group of the German Society of Endocrinology, whose members supported this textbook from its inception and contributed several chapters. We are proud and grateful that many eminent international experts supported the project with enthusiasm: Experts from institutions in 12 countries are among the authors. Collectively, the chapters include copious cutting-edge insights. To facilitate accessibility of the information across disciplines, rich illustrations are included as a special feature of the book, and key points at the ends of the chapters emphasize the authors’ core statements. We hope and trust that this textbook will inspire its readers and provide answers to questions in the highly complex interdisciplinary and interprofessional field of pituitary tumors. We would be most satisfied if the textbook contributes to the benefit of our patients suffering from pituitary tumors
Introduction
Hypothalamic-pituitary regulation of target organs (e.g., thyroid, adrenal, and gonads) relies on specific pathways. If chemical messengers (e.g., hormones and neurotransmitters) are involved, three different functional principles are of importance: The messengers can act on effector cells themselves (autocrine effect), they can influence neighboring cells (paracrine effect), or they can reach their targets via the systemic circulation (endocrine effect). A second pathway of communication is the release of electrical action potentials, achieving rapid and targeted signal transmission. A clear differentiation between the two systems is often not possible because many hormones (e.g., catecholamines) are both endocrine messengers and neurotransmitters. The key integrative organ of vegetative functions is the hypothalamus, which forms the floor and part of the side and anterior walls of the third ventricle. It transforms electric signals of the central nervous system (CNS) into endocrine messengers, thereby coordinating the body’s most important regulatory processes. The latter include control of breathing, body temperature, circulation, reproduction, nutrients, and water intake as well as the wake/sleep cycle. This explains the high number of afferent and efferent nerve bundles connecting the hypothalamus with other CNS structures. While afferent nerve pathways are mainly connected with the cerebral cortex, limbic system, and the thalamus, efferent pathways travel to the posterior pituitary (syn. neurohypophysis) and the vegetative centers of brain stem and spinal cord. The hypothalamus communicates with its surrounding structures via both electrical signal transduction and specific control hormones. The latter are secreted into the capillaries of the median eminence and reach the capillary bed of the pituitary gland via the portal circulation. That way, they either induce (as releasing hormones) or inhibit (as inhibiting hormones) local hormone synthesis (Table 1). The pituitary gland is the hormonal executive organ of the hypothalamus. It is about the size of a pea, is located in the sella turcica of the sphenoid bone, and is composed of two parts that differ from an evolutionary point of view in their anatomy-morphology and functions. The anterior pituitary (syn. adenohypophysis) originates embryologically from the splitting of the roof of the developing mouth (syn. Rathke’s pouch). Influenced by transcription factors the pluripotential precursor cells differentiate into specialized cell formations responsible for production of the various anterior pituitary hormones (Table 2). By contrast the posterior pituitary is part of the diencephalon, which merges during embryogenesis with the anterior pituitary via the pituitary stalk (syn. infundibulum). If this connection is impaired, diminished pituitary hormone production with subsequent anterior pituitary insufficiency may be the consequence (since hypothalamic hormones are not able to reach the pituitary when the portal vasculature of the pituitary stalk is discontinuous). Thus the hypothalamus and pituitary gland are closely connected not only functionally but also morphologically. The characteristic interactions between the hypothalamus, the pituitary gland, and the individual target organs are described in more detail in the following sections.
