FLOW800−guided microsurgical resection of a brainstem hemangioblastoma with AVM−like features: a case report and technical note

Background Brainstem hemangioblastomas (HBs) are rare, highly vascularized benign tumors that pose significant surgical challenges due to their deep location, proximity to critical neural structures, and arteriovenous malformation (AVM)-like angioarchitecture. Preoperative embolization carries a high risk of edema or hemorrhage, and piecemeal resection is often impossible. The intraoperative use of FLOW800 color-coded fluorescence angiography may improve real-time hemodynamic assessment, but its application in brainstem HB surgery is rarely reported. Case presentation A 39-year-old female presented with headache, dizziness, and ataxia. Imaging revealed a brainstem HB involving the fourth ventricle and cerebellar vermis, with obstructive hydrocephalus and syringomyelia. The patient underwent a suboccipital median approach. Intraoperatively, FLOW800 under a Zeiss microscope was used to differentiate feeding arteries from draining veins. Following FLOW800 guidance, the tumor was dissected circumferentially with en bloc resection, paying extreme gentleness to the brainstem interface, especially at the lower pole adherent to the medulla oblongata. Gross-total resection (2.3 cm × 3.0 cm × 2.4 cm) was achieved with minimal blood loss. The patient recovered well, was extubated 4 hours postoperatively, and had no new cranial nerve or respiratory deficits. Histopathology and immunohistochemistry (inhibin-α+/CD10–/GFAP–/EMA–) confirmed HB and excluded mimics. Conclusion For brainstem HBs with AVM-like hypervascularity, FLOW800-guided en bloc peripheral dissection combined with ultra-gentle manipulation of the tumor-brainstem interface allows safe gross-total resection without preoperative embolization. This case supports the routine intraoperative use of FLOW800 in selected brainstem HBs.