Near-infrared autofluorescence to differentiate pituitary gland from tumor in endoscopic endonasal resection of pituitary adenomas: illustrative cases

BACKGROUND: Differentiating pituitary adenoma from normal pituitary gland during endoscopic transsphenoidal surgery can be challenging, yet this distinction is critical for maximizing tumor resection while preserving endocrine function. Near-infrared autofluorescence (NIRAF) is an established intraoperative adjunct in endocrine surgery and may be applicable to pituitary surgery. OBSERVATIONS: The authors present the cases of 3 patients undergoing endoscopic endonasal transsphenoidal pituitary surgery in which a probe-based NIRAF device was used intraoperatively to differentiate adenomatous tissue from normal gland. In all cases, normal pituitary tissue demonstrated markedly higher autofluorescence than tumor. Peak detection levels for tumor ranged from 50 to 97, whereas those for normal gland ranged from 283 to 514. Detection ratios showed consistent separation between tissue types (tumor 2.3-2.7 vs normal gland 9.6-15.7). This reproducible pattern provided real-time intraoperative guidance and facilitated safe gross-total resection. LESSONS: Probe-based NIRAF reliably distinguished normal pituitary gland from adenomatous tissue in this small series, and the separation was consistent despite variation in absolute values, suggesting that intraoperative interpretation may depend more on relative signal contrast than on absolute thresholds. Larger prospective studies are needed to establish diagnostic thresholds and to determine effects on extent of resection and postoperative endocrine function. https://thejns.org/doi/10.3171/CASE26545.