The pituitary "incidentaloma".

PURPOSE: To review evidence related to sellar masses that might be found incidentally on various radiologic procedures, including their differential diagnosis and recommendations for their evaluation and treatment. DATA IDENTIFICATION: An English-language literature search using bibliographic reviews of textbooks and review articles. STUDY SELECTION: Articles were selected on the basis of providing data on the autopsy prevalence of sellar masses, the radiologic and endocrinologic evaluation of such masses, and the prognostic aspects of pituitary adenomas. DATA EXTRACTION: Twelve studies relating autopsy findings, 6 studies describing radiologic characteristics, and 26 articles reviewing various endocrine aspects of pituitary adenomas were evaluated. RESULTS OF DATA SYNTHESIS: Pituitary adenoma is the most common incidental sellar mass. Scanning techniques are of great importance in differentiating the pituitary adenoma from other mass lesions. Autopsy and radiologic studies suggest that microadenomas (less than 10 mm in diameter) may be present in 10% to 20% of the population but that macroadenomas (greater than 10 mm in diameter) are quite rare. Hormone oversecretion by an adenoma may be asymptomatic but, when present, is very helpful in the differential diagnosis.
CONCLUSIONS: For adenomas found to be hypersecreting, therapy is as indicated for that specific tumor type. If there is no evidence of hormone oversecretion from microadenomas, we suggest a conservative approach with repeat scanning done at yearly intervals, initially, and subsequently less frequently. Macroadenomas, because they have already indicated some propensity for growth, should either be surgically removed or, if completely asymptomatic, followed closely with repeat scans at 6- to 12-month intervals.