Aggressive Pituitary Tumors

Pituitary adenomas are common intracranial tumors that are mainly considered as benign. Rarely, these tumors can exhibit an aggressive behavior, characterized by gross invasion of the surrounding tissues, resistance to conventional treatment leading to early and frequent recurrences. Even more rarely, pituitary tumors can give rise to cerebrospinal or systemic metastases qualifying as pituitary carcinomas according to the latest WHO definition. In the same classification, a subset of tumors with relatively distinct histopathological features was identified and defined as atypical adenomas designated to follow a more aggressive clinical course. This classification, although clinically useful, does not provide an accurate correlation between histopathological findings and the clinical behavior of these tumors, neither is it adequate to convey the precise features of ‘aggressive’ tumors. Thus, ‘aggressive’ pituitary adenomas need to be properly defined with clinical, radiological, histological and molecular markers in order to identify patients at increased risk of early recurrence or subsequent tumor progression. At present, no single marker or classification system of pituitary tumor aggressiveness exists, and clinically useful information in the literature is insufficient to guide diagnostic and therapeutic decisions. Treatment of patients with aggressive pituitary tuReceived: July 30, 2014 Accepted after revision: December 25, 2014 Published online: January 5, 2015 Assoc. Prof. Gregory Kaltsas, MD, FRCP Endocrine Unit, Department of Pathophysiology National University of Athens Mikras Asias 75, GR–11527 Athens (Greece) E-Mail gkaltsas @ endo.gr © 2015 S. Karger AG, Basel 0028–3835/15/1012–0087$39.50/0