Silent pituitary adenomas: review and clinical cases

Silent, or clinically nonfunctioning adenomas are morphologically heterogeneous group, characterized by positive immunoreactivity for one or more hormones classically secreted by normal pituitary cells but without clinical expression. Although in some occasions enhanced or changed secretory activity can develop over time. According to immunoreactivity they are divided into "silent" gonado-, cortico-, somato -, mammo – and thyrotropinomas, oncocytomas, «zero-cell» tumors. All types of "silent" adenomas have different biological activity, secretory capacity and outcomes in the postoperative period. This series of clinical cases shows more «aggressiveness», a higher risk of relapse for "silent" cortico- and somatotropinomas. Immunohistochemical analysis of residual tissue can be used to identify patients with high risk of recurrence, to develop optimal treatment and follow-up.