A specialized elongated ventricular ependymal cell that has processes that extend to the outer, or pial, surface of the CNS. A tanycyte is found in the adult brain, specifically in the third ventricle, cerebral aqueduct, spinal canal, and floor of the fourth ventricle. This cell type is involved in hormonal regulation, gatekeeping molecules between the bloodstream and cerebrospinal fluid, metabolic sensing, and regulating food intake.