Pituitary Carcinomas

Abstract

Pituitary carcinoma is a extremely rare and is characterized by a very poor prognosis. Even if at diagnosis the presence of metastases is required to define a pituitary carcinoma, the lesion was almost invariably diagnosed first as a benign pituitary tumor, that after a variable period of latency, ranging from few months to many years, changed its natural course to an aggressive pituitary tumor poorly responsive to therapy. Recent studies have partially clarified its molecular pathogenesis and found possible markers of aggressiveness in order to make an earlier diagnosis, when still treatment could improve their prognosis. Most pituitary carcinomas are functioning, and ACTH- and PRL-secreting carcinomas are the most frequent. Treatment includes surgery, radiotherapy, medical therapy and chemotherapy, but the poor results with current therapies should prompt all investigators to better understand its pathogenesis and searching new molecular targets for treatments.

Pituitary Adenomas – Clinico-Pathological, Immunohistochemical and Ultrastructural Study

“…This factor is not necessarily indicative of malignancy, because tumor growth is slow and metastases are rare. The histological aspect is not different from the rare carcinoma cases (Colao et al, 2010;Crocker, 1978;Kaltsas et al, 2005;Schteithauer et al, 2005;Tena-Suck et al, 2006;).…”

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

“…Pituitary tumors do not progress like other solid tumors, which start with hyperplasia, pass a state of benign adenoma and end up with an aggressive carcinoma (Farrell & Clayton 1998, Melmed 2008, Colao et al 2010. Pituitary cells are among the few epithelial cell types that rarely undergo malignant transformation.…”

“…Different mechanisms and factors involved in the initiation and progression of pituitary adenomas have been described, including cell-cycle deregulation, overexpression of growth factors, oncogenes and hormones, defective signaling pathways and an altered intrapituitary microenvironment (Clayton & Farrell 2004, Farrell 2006, Dworakowska & Grossman 2009, Colao et al 2010, Vandeva et al 2010, Melmed 2011, Perez-Castro et al 2012, as well as inherited or somatic mutations in genes such as AIP (Vierimaa et al 2006), GPR101 (Trivellin et al 2014) and USP8 (Reincke et al 2015). The recent characterization of pituitary stem cells (Fauquier et al 2008, Garcia-Lavandeira et al 2009, 2015, Vankelecom & Gremeaux 2010 implies the possibility of defining their mechanisms involved not only in pituitary cell renewal but also in pituitary tumorigenesis.…”

Adult Pituitary Stem Cells: From Pituitary Plasticity to Adenoma Development

“…Pituitary adenomas indeed are highly prevalent in humans, representing up to 15% of all diagnosed intracranial neoplasms and found in 10–25% of unselected people at autopsy [for review see [59,60,61]. They are typically benign tumors that only rarely metastasize [62], but can cause severe morbidity, displaying compression symptoms (including visual defects and hypopituitarism), and major endocrine syndromes, due to uncontrolled hormone secretion. To date, the molecular and cellular pathogenesis of pituitary tumors is largely unknown [63].…”