Use of Intraoperative Tumor Consistency Grading to Guide Resection Technique of Pituitary Neuroendocrine Tumors

Pituitary neuroendocrine tumors (PitNETs) are common intracranial neoplasms for which the endoscopic endonasal trans-sphenoidal approach has become the gold standard for surgical management. Resection can be further categorized as extracapsular resection (ER), during which the tumor pseudocapsule is dissected from surrounding structures and majority of tumor is delivered en bloc , or intracapsular resection (IR) during which the tumor is debulked, suctioned, and removed from within the pseudocapsule. This study assessed the relationship between PitNET consistency and intraoperative resection strategy.

In total, 345 patients who underwent resection of PitNETs at the USC Pituitary Center between 2016 and 2023 were retrospectively studied. Variables collected included tumor consistency (graded prospectively), surgical resection technique, maximum tumor diameter, Knosp cavernous sinus invasion (CSI) score, hormonal subtype, extent of resection, length of hospital stay, and complication rates. Univariable and multivariable analyses were performed to determine associations between resection techniques.

ER was used in 23 patients (7%) and IR in 322 patients (93%). 271 patients (78.55%) had a soft-to-average PitNET with consistency score of 1-3, whereas 74 patients (21.45%) had a firm consistency score of 4-5. Twenty-one (91.30%) of 23 ER-resected PitNETs were firm, compared with 53 (16.46%) of 322 IR-resected PitNETs ( P < .001). ER-resected tumors were on average smaller (20.39 vs 24.87 mm, P = .023) and demonstrated less CSI (Knosp score 3-4 in 8.70% vs 34.78%, P = .021). In 74 firm PitNETs, ER was used more commonly in Knosp 0-2 cases than Knosp 3-4 cases (90.48% vs 9.52%, P = .033). There was no association between the use of ER and increased surgical complications ( P > .05).

Extracapsular resection of PitNETs is a viable, safe, and often necessary resection technique that should be considered for smaller, firm PitNETs, particularly those without significant CSI. Most soft PitNETs can be addressed using an internal debulking/suction strategy or hybrid strategy.