Letter to the Editor: Endoscopic endonasal transsphenoidal approach to pituitary adenomas

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TO THE EDITOR: We read with great interest the article by Juraschka et al.1 from the University of Toronto, Canada (Juraschka K, Khan OH, Godoy BL, et al: Endoscopic endonasal transsphenoidal approach to large and giant pituitary adenomas: institutional experience and predictors of extent of resection. J Neurosurg 121:75–83, July 2014). They timely and properly focus the readers' attention on the particular clinical and surgical challenges in the management of giant pituitary adenomas, which constitute a subgroup of lesions that have been classically defined by a maximum diameter > 4 cm. They consider giant adenomas those tumors with a volume of at least 10 cm3 or a maximum diameter ≥ 3 cm. As a matter of fact, in their study, in which they used the above-mentioned inclusion criteria, the authors analyzed the clinical and surgical outcomes in a series of 73 patients who underwent surgery via an endoscopic endonasal transsphenoidal approach at their institution in a 6.5-year timeframe. They report that they used, in almost one-third of their patients, an extended endoscopic approach.

Obviously, the majority of their patients harbored a clinically nonfunctioning pituitary macroadenoma and complained of visual disturbances (either visual acuity and/or visual field defects) and/or endocrine hypofunction. According to preoperative MRI, a cystic component was present in 30.1% of tumors, a hemorrhagic component in 24.7%, sphenoid sinus invasion in 35.6%, anterior extension in 16.4%, posterior extension in 31.5%, suprasellar lateral extension in 26.0%, optic nerve compression in 94.5%, and hydrocephalus in 5.5%.

Such percentages, particularly the 35.6% with a component inside the sphenoid sinus or the 30.1% with the presence of a cystic or hemorrhagic lesion, in our opinion, are confusing since they do not actually indicate only those tumors that pose technical difficulties in their surgical management. In other words, what causes the difficulties in surgically treating giant adenomas are the supra-parasellar components of the tumor, which are those involving the most critical neurovascular structures, having a greater risk of injury by the surgeon. Indeed, a tumor with a diameter measuring more than 3 or 4 cm, but with a reasonable part of it extending inside the sphenoid sinus or more downward, does not necessarily pose the same technical risks or have the same outcome as a surgically treated mass with a predominant component in the supraparasellar areas, even if that mass has a smaller diameter. Similarly, an adenoma with a soft consistency or with a cystic component is easier to remove than a same-sized lesion with a harder texture; or a tumor predominantly in the midline has a location that is certainly more favorable for removal than a lesion with eccentric lateral paraventricular extensions. It is easily understood that the possibility of achieving gross-total removal is greater for adenomas, even giant ones, with more surgically favorable features (sizable component in the sphenoid sinus, soft consistency, no invasion of the cavernous sinuses, and so forth) than for a big adenoma with unfavorable features.

In the authors' study, however, considering such a heterogeneous group of lesions together, pooled only on the basis of measures and not stratifying them on the basis of their different characteristics, might in some way have corrupted the actual extent of resection rate, the overall visual outcome, and the percentage of complications, which deeply differ from one another if we consider the direction and site of growth of the neoplasm. Thus, we do not agree with the authors when they conclude that sphenoid sinus invasion may represent a tumor characteristic that decreases the likelihood of successful and complete endoscopic transsphenoidal surgery. The presence of a component in the sphenoid sinus, and therefore far from the neurovascular structures, might be considered a favorable feature in obtaining greater tumor debulking. On the contrary, in our experience, the true giant pituitary adenomas that extend mainly in the intracranial compartment present a greater rate of complications.

Finally, we are sincerely thankful to the authors for having focused attention on the surgical management of giant pituitary adenomas and the uncommon challenges they pose regarding the predictability of obtaining a gross-total removal and improving preoperative deficits.

DISCLOSURE

The authors report no conflict of interest.

Reference

1

Juraschka KKhan OHGodoy BLMonsalves EKilian AKrischek B: Endoscopic endonasal transsphenoidal approach to large and giant pituitary adenomas: institutional experience and predictors of extent of resection. J Neurosurg 121:75832014

Response

No response was received from the authors of the original article.

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Article Information

INCLUDE WHEN CITING Published online December 12, 2014; DOI: 10.3171/2014.8.JNS141716.

© AANS, except where prohibited by US copyright law.

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References

1

Juraschka KKhan OHGodoy BLMonsalves EKilian AKrischek B: Endoscopic endonasal transsphenoidal approach to large and giant pituitary adenomas: institutional experience and predictors of extent of resection. J Neurosurg 121:75832014

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