Surgical management of giant pituitary adenomas

Abstract

Pituitary tumors whose maximum dimension exceeds 4 cm are defined as giant pituitary adenomas. Such giant pituitary tumors are rare and their management is a formidable and controversial problem. Of the 850 pituitary tumors operated upon during the period between 1995 and 2002 in the authors' Institute, there were 118 ‘hormonally inactive’ giant pituitary tumors. The tumors were divided into four grades, depending on the extensions and the nature of their meningeal coverings. The grades reflected an increasing order of invasiveness of adjacent dural and arachnoidal compartments. Giant pituitary tumors, which remained within the confines of sellar dura and under the diaphragma sellae and did not enter into the compartment of cavernous sinus, were classified as Grade I (54 cases); those which transgressed the medial wall of the cavernous sinus were classified as Grade II (38 cases); those which elevated the dura of the superior wall of the cavernous sinus were classified as Grade III (24 cases); and those with supradiaphragmatic–subarachnoid extension were classified as Grade IV (2 cases). Radical surgery by a transsphenoidal route was seen to be suitable in Grade I–III pituitary tumors. It offered a reasonable opportunity for radical tumor resection and recovery of vision. Biopsy of the tumor followed by radiotherapy could be suitable for Grade IV pituitary tumors.