Treatment of Large Pituitary Adenoma

Abstract

There are only a few reports on the surgical results in cases of very large pituitary adenomas. Several authors have indicated that the operative mortality in cases of giant pituitary adenoma is considerably higher than that in cases of usual pituitary adenoma. Therefore, surgical indication and approach for very large pituitary adenomas are controversial. In order to determine the surgical indication and approach for very large pituitary adenomas the authors examined 35 cases of very large pituitary adenoma with suprasellar extension higher than that of type B according to the classification by Wilson, or with intracranial tumor lobules extending extrasellarly in more than two directions. Surgical results were divided into three groups as follows: 1) cases from pre-computed tomography (CT) era, 2) cases operated on by transcranial approach in post-CT era, and 3) cases operated on by transsphenoidal approach in post-CT era. Several characteristic features were obtained as listed below: 1) Spontaneous intratumoral hemorrhage is apt to occur more frequently in the very large adenoma cases than in ordinary cases. Therefore, surgical treatment of the very large adenoma cases should be performed very carefully. 2) Intratumoral hemorrhage and swelling of the residual tumor in cases with marked posterior extension are the crucial cause of postoperative death. However, radical removal often aggravates preoperative dysfunction of the hypothalamohypophyseal system, and progressive disorders of the hypothalamo-hypophyseal system can be another cause of death. Therefore, intracapsular decompression is advised. 3) Transsphenoidal intracapsular removal shows less mortality and morbidity than the transcranial approach in cases with postero-superior extension. A combined supra-infrasellar approach seems to be indicated for tumors with prominent parasellar or frontal extension. 4) Postoperative radiation therapy is very effective for reducing residual tumors in size and for prevention of their recurrence.