Palatal ancient schwannoma: optical, immunohistochemical and ultrastructural study with literature review.

Schwannoma or neurilemmoma is a benign encapsulated slow-growing tumor that originates from a Schwann cell of a nerve, and is rare at intraoral locations. Different histological variants of schwannomas have been described, of these degenerative or ancient schwannoma is probably one of the least common in the oral cavity with only 16 previously reported cases, of which only one has been described in palatal location. Although ancient schwannoma shows particular characteristics, it is difficult to diagnose based on clinical and imaging appearance alone; as a result, morphological examination assisted by ancillary techniques is necessary to establish a definite diagnosis. We present a clinicopathological description of this rare variant of schwannoma, located in an unusual intraoral site, of a 26-year-old female. We illustrate the optical, immunohistochemical and ultrastructural characterization that aid diagnosis, as well as providing a review of the relevant published data of this unusual tumor.