Clinical Biology of the Pituitary Adenoma.

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences.

Pituitary Neoplasm Nomenclature Workshop: Does Adenoma Stand the Test of Time?

The designates pituitary neoplasms as adenomas. A proposed nomenclature change to pituitary neuroendocrine tumors (PitNETs) has been met with concern by some stakeholder groups. The Pituitary Society coordinated the Pituitary Neoplasm Nomenclature (PANOMEN) workshop to address the topic.

Pituitary society guidance: pituitary disease management and patient care recommendations during the COVID-19 pandemic-an international perspective.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the viral strain that has caused the coronavirus disease 2019 (COVID-19) pandemic, has presented healthcare systems around the world with an unprecedented challenge. In locations with significant rates of viral transmission, social distancing measures and enforced 'lockdowns' are the new 'norm' as governments try to prevent healthcare services from being overwhelmed. However, with these measures have come important challenges for the delivery of existing services for other diseases and conditions.

Pituitary pathology in traumatic brain injury: a review.

Purpose: Traumatic brain injury most commonly affects young adults under the age of 35 and frequently results in reduced quality of life, disability, and death. In long-term survivors, hypopituitarism is a common complication.

Results: Pituitary dysfunction occurs in approximately 20-40% of patients diagnosed with moderate and severe traumatic brain injury giving rise to growth hormone deficiency, hypogonadism, hypothyroidism, hypocortisolism, and central diabetes insipidus.

Physicians' awareness of gadolinium retention and MRI timing practices in the longitudinal management of pituitary tumors: a "Pituitary Society" survey.

Purpose: In view of mounting attention related to possible brain retention of gadolinium-based contrast agents (GBCAs) in patients with normal renal function, our purpose was to detail results from a survey of pituitary experts to assess: 1) the timing interval and frequency of pituitary magnetic resonance imaging (MRI) following surgical and/or medical and/or radiation therapy of pituitary tumors, 2) awareness of the types of GBCAs used and their possible safety issues.

Methods: The Pituitary Society Education Committee composed a survey with 12 multiple choice questions, 8 of which specifically addressed the time interval and frequency of MRI in the longitudinal management of pituitary tumors. The survey was distributed at two meetings; the International Pituitary Neurosurgeons Society conference in San Diego, CA, on February 18th, 2018, and the Pituitary Society Membership and Career Development Forum, Chicago, IL on March 18th, 2018.

Temozolomide and Pituitary Tumors: Current Understanding, Unresolved Issues, and Future Directions.

Temozolomide, an alkylating agent, initially used in the treatment of gliomas was expanded to include pituitary tumors in 2006. After 12 years of use, temozolomide has shown a notable advancement in pituitary tumor treatment with a remarkable improvement rate in the 5-year overall survival and 5-year progression-free survival in both aggressive pituitary adenomas and pituitary carcinomas. In this paper, we review the mechanism of action of temozolomide as alkylating agent, its interaction with deoxyribonucleic acid repair systems, therapeutic effects in pituitary tumors, unresolved issues, and future directions relating to new possibilities of targeted therapy.

65 YEARS OF THE DOUBLE HELIX: Treatment of pituitary tumors with temozolomide: an update.

Temozolomide is an alkylating chemotherapeutic agent used in malignant neuroendocrine neoplasia, melanoma, brain metastases and an essential component of adjuvant therapy in the treatment of glioblastoma multiforme and anaplastic astrocytoma. Since 2006, it has been used for the treatment of pituitary carcinomas and aggressive pituitary adenomas. Here, we discuss the current indications and results of temozolomide therapy in pituitary tumors, as well as frequently asked questions regarding temozolomide treatment, duration of therapy, dosage, tumor recurrence and resistance.

gene mutations in endocrine tumors.

In this review, the importance of the gene in the function of endocrine cells is discussed. There is conclusive evidence that mutations play a crucial role in the development, progression, cell proliferation, therapeutic responsiveness and behavior of several endocrine tumors. We review the literature of gene mutations in thyroid, parathyroid, pituitary, pineal gland, endocrine pancreas, paragangliomas, medullary, adrenocortical, ovarian and testicular tumors.

Alpha subunit in clinically non-functioning pituitary adenomas: An immunohistochemical study.

Pituitary adenomas may be classified as either functioning or non-functioning, depending on whether excess hormone secretion can be clinically identified. Of the six hormones produced in the anterior pituitary, TSH, FSH and LH are known as glycoproteins and contain two subunits (α and β). While α-subunit is identical within all of them, each β-subunit is unique and biologically specific.

Selective molecular biomarkers to predict biologic behavior in pituitary tumors.

To date, several cell proliferation markers, apoptosis, vascular markers, oncogenes, tumor suppressor genes, cell cycle mediators, microRNA (miRNAs), and long noncoding RNAs (lncRNAs) have been identified to be involved in the tumorigenesis, migration, proliferation and invasiveness of pituitary adenomas. There are still no reliable morphologic markers predictive of pituitary adenoma recurrence. Recent scientific research introduced new techniques to enable us to attain new information on the genesis and biologic behavior of pituitary adenomas.

Immunoglobulin G4 (IgG4)-Related Hypophysitis.

We report two different cases of IgG4-related hypophysitis. In the first case, a pituitary lesion was accompanied by lymphocytic meningitis possibly mimicking tuberculous meningitis. The second case was unassociated with involvement of other organs.

Vasculogenic Mimicry in Clinically Non-functioning Pituitary Adenomas: a Histologic Study.

The term "vasculogenic mimicry" (VM) refers to the phenomenon in which vascular-like channels, which are not lined by endothelial cells, are formed in tumors. Since its discovery in 1999, it has been observed in several tumor types and is proposed to provide blood perfusion to tumors in absence of co-apted or neo-angiogenic blood vessels. Pituitary tumors are generally slow growing, benign adenomas which are less vascularized than the normal pituitary gland.

Pathology of GH-producing pituitary adenomas and GH cell hyperplasia of the pituitary.

Introduction: Histologic, immunohistochemical and electron microscopic studies have provided conclusive evidence that a marked diversity exists between tumors which secrete growth hormone (GH) in excess. GH cell hyperplasia can also be associated with acromegaly in patients with extrapituitary GH-releasing hormone secreting tumors or in familial pituitary tumor syndromes.

Materials And Methods: A literature search was performed for information regarding pathology, GH-producing tumors and acromegaly.

Biomarkers of pituitary carcinomas.

Pituitary carcinoma is a rare tumor originating from adenohypophyseal cells. Currently, diverse pathogenetic mechanisms, i.e.

Arginine vasopressin (AVP): a review of its historical perspectives, current research and multifunctional role in the hypothalamo-hypophysial system.

Introduction: This publication reviews the function of arginine vasopressin and focuses on the morphologic and functional correlation between the hormone and its effect on stress, the hypophysial-adrenocortical axis, neuroimmune responses, renal function and corticotroph pituitary tumors.

Materials And Methods: A literature review was performed using various search engines for information regarding the morphology and the multifunctional role of arginine vasopressin.

Results: Although a large number of studies were published discussing these interactions, there are several important areas that are still obscure.

Progress in the Diagnosis and Classification of Pituitary Adenomas.

Pituitary adenomas are common neoplasms. Their classification is based upon size, invasion of adjacent structures, sporadic or familial cases, biochemical activity, clinical manifestations, morphological characteristics, response to treatment and recurrence. Although they are considered benign tumors, some of them are difficult to treat due to their tendency to recur despite standardized treatment.

Autophagy in endocrine tumors.

Autophagy is an important intracellular process involving the degradation of cytoplasmic components. It is involved in both physiological and pathological conditions, including cancer. The role of autophagy in cancer is described as a 'double-edged sword,' a term that reflects its known participation in tumor suppression, tumor survival and tumor cell proliferation.

Invasive, atypical and aggressive pituitary adenomas and carcinomas.

Aggressive pituitary adenomas have a high risk of recurrence, a lack of therapeutic response, and resistance to conventional treatment. So far, no satisfactory biomarkers are available for predicting their behavior. Some specific pituitary adenoma histotypes are more prone to follow an aggressive behavior.

Treatment of invasive silent somatotroph pituitary adenoma with temozolomide. Report of a case and review of the literature.

Improved imaging techniques have contributed to increased diagnosis of pituitary tumors. These tumor types can be microadenomas or macroadenomas and can either be functional or non-functional. Atypical or aggressive pituitary adenomas are tumors that rapidly increase in size and may invade into the suprasellar or parasellar regions.

Crooke's cell tumors of the pituitary.

Crooke's cell adenomas are a rare type of pituitary neoplasm. They produce adrenocorticotropic hormone causing Cushing's disease or may be endocrinologically silent. These tumors are usually invasive, may exhibit aggressive clinical behavior, and often recur with a low success of cure after reoperation and/or radiotherapy.

Human kallikrein 10 in surgically removed human pituitary adenomas.

Objective: Human kallikrein-like peptidase 10 (KLK10), a serine protease, plays an important role in the regulation of cell proliferation and tumor growth. In this work, we investigated KLK10 immunoexpression in various types of surgically removed human pituitary tumors.

Design: Specimens were fixed in formalin and embedded in paraffin.

Human kallikrein 10 expression in surgically removed human pituitary corticotroph adenomas: an immunohistochemical study.

Human kallikrein 10 (hk10), a secreted serine protease, was reported to function as a tumor suppressor. hK10 immunoexpression has been demonstrated in lactrotrophs and corticotrophs of the nontumorous human adenohypophysis. In the present study, for the first time we report hK10 immunoexpression in various surgically removed corticotroph adenoma subtypes.

Current status on histological classification in Cushing's disease.

Introduction: Managing Cushing's disease remains a challenge. Surgery is the first option of treatment and it offers a high success rate. Even in cases where biochemical remission is not achieved, it is crucial to obtain surgical tissue for morphological diagnosis because the therapeutic approach can be modified according to the findings.