Intracavernous extension of pituitary adenomas.

Frequency of intracavernous invasion by a pituitary adenoma varies from 9 % to 40 % depending on the publications. Without putting off the possibility of true intracavernous invasion, it seems less frequent than evocated on C T-Scan and/or MRI data. We studied 153 files of pituitary adenomas operated upon recently: 72 prolactinomas (47.3 %), 30 GH-secreting adenomas (19.7 % ), 7 corticotrop adenomas (4.6%), 44 non secreting adenomas (28.3 %). 108 p atients (70.4 %) harboured a macroadenoma (diameter > 10 mm). A suprasellar expansion was seen 90 Limes on CT-Scan and/or MRI views. 19 times (17.7 % of macroadenomas, 12.5 % of the whole series) MRI evocated an infiltration of one or both cavernous sinuses (CS). Such data were found 3 times before 1991. 16 times since 1991, i.e. since MRI is systematically performed preop eratively. Except in two patients who respectively presented with a large i ntraorbital or temporal expansion, we have not been able to confirm the rea lity of the intracavernous invasion. We think that most of CT-Scan or MRT d ata of so-called intracavernous invasion correspond in fact to a compressio n or to a fingerglove invagination of the medial wall of the CS. in fact, a natomical studies by Harris & Rhoton (1976) and by Taptas (1990) demonstrat ed that such an invagination of the medial wall exists in almost one third of normal pituitary glands. These data must bring up to much carefulness wh en considering a possible pathological CS invasion by a macroadenoma. There fore, it should be thoroughly assessed with anatomoradiological and radio-s urgical correlations.