Although an important practical problem, firm fibrous tumors have produced relatively little discussion in the literature. They may be difficult and dangerous to access from below, and the transcranial route may be preferred in such cases (11) or there may be an argument for leaving them alone. If the capsule of a firm tumor is closely applied to the chiasm, chiasmal vessels, pituitary stalk, or hypothalamus, then the traction required to remove it from below is associated with high morbidity from damage to these structures. The firm nature of the tumor may be discovered during a transsphenoidal operation, or the evidence may be inferred from preoperative radiology. Snow found that 70% of tumors that were isointense with surrounding brain on T2-weighted MRI were of firm consistency at surgery (12).
Bromocriptine treatment is associated with an increased incidence of fibrosis (13), and this may be anticipated in patients who have had a long preoperative course of the drug. It begs the question of the indications for the operation. Increased fibrosis has also been reported in patients with somatotroph adenomas pretreated with somatostatin analogs (14,15), although this is not our experience. Patterson found that previous radiotherapy correlated with an increased incidence of a firm tumor at operation (16). Rather than use a craniotomy in these cases, Abe observed that the tumor remnant descended into the sella during a 2-mo period after transsphenoidal operation (17). He then employed a second transsphenoidal operation to remove the remnant; we have occasionally used this approach.
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