Advances in understanding pituitary tumors

Abstract

Pituitary tumors are common in the general population. Since neuroimaging techniques have improved, pituitary tumors are more often diagnosed incidentally. About 16.7% of the general population show changes in the pituitary gland. Predominantly, pituitary tumors are benign pituitary adenomas. Pituitary carcinomas or aggressive pituitary tumors are extremely rare. They might develop from benign adenomas. New genetic and epigenetic abnormalities help us to understand pituitary tumorigenesis and might lead to therapeutical targeting drugs in the future. Macroadenomas (>1 cm) can lead to visual field disturbances, compression of cranial nerves, hypopituitarism, and infiltration of the cavernous sinuses. The functional status of the pituitary tumor is important. About half to one third of all pituitary tumors are non-functioning pituitary adenomas. The other pituitary tumors show a specific pattern of hormone secretion. About 25% to 41% of all pituitary tumors are prolactinomas, acromegaly with production of growth hormone represents 10% to 15% of adenomas, Cushing's disease with production of adrenocorticotropic hormone accounts for 10%, and other hormonal characteristics are less common. Transsphenoidal resection and total adenomectomy are desirable. Radiosurgery has enriched the surgical treatment options. Surgical treatment is the intervention of choice except for prolactinomas, where pharmaceutical treatment is recommended. Pharmaceutical treatment consists of dopamine agonists such as cabergoline and somatostatin analogues that include octreotide and pasireotide; retinoic acid is of theoretical interest while peroxisome proliferator-activated receptor-gamma-ligands are not clinically useful. In acromegaly, pegvisomant is a further treatment option. Temozolomide should be considered in aggressive pituitary tumors. In general, pharmaceutical options developed recently have extended the repertoire of treatment possibilities of pituitary tumors.

Topoisomerase 2 alpha as a prognostic factor in pituitary tumors

“…Vidal et al limited [36][37][38]. In our study, these tumors showed the highest values of Topo2A expression and a high recurrence rate.…”

Topoisomerase IIα as a prognostic factor in pituitary tumors

“…The possibility exists to introduce agents inhibiting the expression of topo IIα in hormone immunonegative adenomas where pharmacotherapy is currently limited. [37][38][39] In our study, these tumors showed the highest topo IIα expression levels and a high recurrence rate.…”

Programmed cell senescence: role of IL-6 in the pituitary

“…Elevated levels of cytokines alter the physiological hormone production to adapt the R245 Review m sapochnik and others IL-6 and pituitary senescence endocrine system to the needs of the organism to respond adequately to pathogens. Pituitary tumors are mostly benign, non-metastatic and monoclonal neoplasms constituted by cells of the adeno-pituitary gland, which generally cause small lesions and present a slow growth (Scheithauer et al 2006, Dworakowska & Grossman 2009, Melmed 2011, 2015, Lake et al 2013, Kopczak et al 2014. The pathophysiological consequences of a pituitary adenoma are related to overproduction of particular pituitary hormones or due to tumor compression and damage to the normal pituitary and vital structures surrounding it (Yu & Melmed 2010).…”