[P-2235] MACROSCOPIC ALTERATIONS IN PITUITARY TUMORS AFTER TRANSESPHENOIDAL SURGERY RELATIONSHIP BETWEEN MR AND INTRAOPERATIVE FINDINGS BY THE TIME OF REOPERATION
Arthur Cukiert, Elcio Machado, Alcione Sousa, Jose A Buratini, Joaquim Vieira, Bernardo Liberman, Jaime Goldman, Maria ER Silva, Katia Nogueira, Martha Huayllas, Luis R Salgado.
Departments of Endocrinology and Neurosurgery, Hospital Brigadeiro, Sao Paulo SP, Brazil.
Transesphenoidal microsurgery represents the technique of choice in the treatment of many sellar lesions such as pituitary adenomas and craniopharyngiomas. Despite the use of careful microsurgical techniques by an experienced neurosurgeon, tumors may be incompletely resected and some patients are submitted to transesphenoidal reoperation for further tumor removal. It is traditionally believed that a second operation has less chances to remove totally the tumor then the first procedure. The introduction of MR in the clinical practice over the last decades made it possible to better study these patients with tumor remnants before reoperation was carried out. In many of these patients, the intraoperative finding consists of a harder tumor encased within a stroma that resembles fibrosis. This paper describes the comparison between intraoperative findings at transesphenoidal (TS) reoperation and pre-reoperation MR imaging.
Ten adult patients with pituitary adenoma and who were reoperated through the TS route were studied. All performed high-resolution MRI before and after (3 months) the first procedure. Six patients had non-functioning adenomas, 2 GH secreting and 2 ACTH secreting tumors. All were operated and reoperated through the TS route by the same surgeon. The surgical procedures were recorded on tape. The interval between the first and second surgery varied from 3 to 9 months (m=5).
In 3 patients (Group I), the MR characteristics of the tumors were similar pre- and post-operatively. In 7 patients (Group II) contrast enhancement was evidently higher post-operatively. In Group I, intraoperative findings at reoperation were similar to those found at the first procedure in terms of bleeding degree, aspect, curettability and consistency. In Group II, intraoperative findings were similar to the previous procedure in 2 but in 5, tumors were found to be harder, bleeding more, encased in fibrotic stroma and difficult to remove with microsurgical curettes. In 3 of these 5 patients only partial removal was possible at reoperation. There was no specific imaging finding capable of distinguishing within the 2 different sets of patients within Group II.
Similar MR findings pre- and postoperatively suggest a similar intraoperative finding. An increase in contrast enhancement after surgery may indicate macroscopic alterations in these tumors. A majority of these tumors would turn harder and more difficult to remove. On the other hand, a minority of these patients with higher contrast enhancement may happen to have similar macroscopic findings at reoperation. Postoperative contrast enhancement patterns should be taken into account while considering reoperation in patients with pituitary tumors.