Fluorescein-Guided Surgery for Malignant Gliomas.

Fluorescein (FS) was first used to visualize malignant brain tumors in 1948. FS accumulates in malignant gliomas where the blood-brain barrier is disrupted and provides intraoperative visualization that is similar to preoperative contrast-enhanced T1 images in which gadolinium accumulation is seen. FS can be viewed under white light, but the use of an operating microscope fitted with a dedicated filter (YELLOW 560 nm Filter, Carl Zeiss Meditec, Oberkochen, Germany) allows us to significantly reduce the dose needed to highlight tumoral tissue. FS is excited at 460-500 nm and emits a green, fluorescent emission wavelength at 540-690 nm. It is virtually free of side effects and has low costs (approximately 6.9 USD each vial: Brazil). Video 1 presents a case of a 63-year-old man who underwent a left temporal craniotomy to remove a temporal polar tumor. The FS is administered at the time of anesthesia before a craniotomy. The tumor was then removed with standard microneurosurgical technique by the alternating use of white light and YELLOW 560 nm filter illumination. The use of FS was found "helpful" to discriminate the brain tissue and tumor tissue (bright yellow). Fluorescein-guided technique with a dedicated filter on the surgical microscope is safe and allows complete resection of high-grade gliomas.