[The causes responsible for recurrence of pituitary adenomas and an evaluation of reoperation effects].

Four hundred and twenty one cases of transfrontal removal of pituitary adenomas were presented. Of these 23 had recurrence of tumor which was confirmed by reoperation and histopathological examination. The rate of recurrence decreased while the patients' age increased. Incomplete removal of the tumor tissue was one of the most important causes of recurrence. Invasiveness was another important cause. Most of the tumors in this series were large and had pathologically proven invasiveness. At the reoperations, there were evidences of worse invasiveness, especially the infiltration of adenomas into the capsules and adjacent structures. There was a case of Nelson's syndrome, suggesting the endocrine causes of recurrence. Apparent adhesion and topographic disorders were found during reoperation, improvement of visual impairment decreased obviously, and the mortality rate increased; therefore, the reoperations should be decided with great deliberation.