Pituitary incidentalomas - How often is too often?

Introduction: Clinical nonfunctional pituitary microadenomas, also known as incidentalomas are accidental observations made due to the application of high resolution imaging techniques as computed tomography or magnetic resonance. There are no standards regarding the follow-up of these tumors and taking into account their increased frequency among general population (during the last years they were based on the high performances of the imaging methods), we decided to study their dimensions and their evolution over time. We have also analysed their behavior with respect to their endocrine phenotype and the minimum period of time needed for the repetition of the imagistic procedure. Aim: To observe the natural evolution of tumors’ dimensions in a group of patients, diagnosed with nonfunctional pituitary microadenomas based opon hormonal measurements and computed tomography scan. Method: There is a retrospective observational study on 149 patients hospitalized in our Clinic between 1994 and 2006. Initially, all the pituitary hormones and the computed tomography were performed. Only nonfunctional microadenomas were included (the maximum diameter 11 mm). 69 patients were examined for a long period of time - 29.75 +/- 24.79 months by CT scan and secretory profile, repeated at different periods of time. Results: At the end of 29.75 months, the aspect of microadenoma was still present, without any statistically significant changes of the diameter. One of the cases became macroadenoma and another proved to be a microprolactinoma. Only 5 cases of all 149 presented a double lesion. No case of pituitary apoplexy was registered. These observations lead to the conclusion that it is not necessary to repeat the computed tomography scan sooner than 2 years once the diagnosis of incidentaloma was established.