RESUMO
Some hypophyseal adenomas are discrete, well-marked lesions, which can be curatively removed by surgical resection, while others seem aggressive, invasive, recidive-prone, most often progressing in spite of any pharmacological, surgical or radiotherapeutical interventions. There is also a great variability within the incidence of aggression and invasion among the various types of hypophyseal immunotypes. Despite their well-differentiated nature and their "benign" constitution, an important number of hypophyseal tumors will be surely invasive within the sclerous, osseous and neural structures. Because the aggressive behavior of invasive adenomas is generally resolved by surgical treatment, this aspect of their biology does not perfectly reflect within their histopathological aspect. In fact, the invasive tumors with local extreme aggression are most often deceiving due to their relatively harmless histopathological aspect. The usual morphological signs of tumor aggression, namely pleomorphism, nuclear atypia, hemorrhage, high cellular and mitotic activity, poorly correlate with the invasive potential of pituitary tumors, with their proliferation capacity, their tendency of post-surgical recurrence or with their global biological behavior.
