Fluorescein-Guided Surgery of Peripheral Nerve Sheath Tumors

The mainstay of peripheral nerve sheath tumors (PNST) treatment is surgical enucleation, which is a pivotal predictor of local control and recurrence. Distinguishing between functional intact nerves and the silent fibers from whence the PNST arose is not always easy to perform; therefore, the development of visualization tool represents a valuable method to better visualize pathological tissue. The potential role of sodium fluorescein (SF) in PNST surgery seems to be promising, both in preclinical applications and in the clinical setting; experimental models have indeed demonstrated that SF causes endoneurial extravasation, confirming the behavior of fluorescein as an unspecific, vascular dye, as it happens for central nervous system tumors. The surgical protocol of fluorescein-guided technique for PNST is based on intravenous SF injection at a low dose of 0.5 or 1 mg/kg, immediately upon completion of general anesthesia. Surgery is performed with the aid of a surgical microscope equipped with an integrated specific fluorescent filter. A bright fluorescence is usually depicted in schwannomas and neurofibromas; in particular, in plexiform neurofibromas, fluorescein seems to play a potential role in improving the rate of resection due to the pathological peculiarities of this histotype. On the contrary, the fluorescence pattern is significantly less evident for malignant PNST, perineuriomas, and hybrid nerve sheath tumors. Fluorescein-guided surgery is a safe and effective technique that allows better identification of the most frequent subtypes of PNST from intact functional nerves.