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

Abstract

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.

Schwannoma of the lower lip mimicking a mucocele in children

“…It has also been highlighted that immunohistochemical positivity for S-100 protein, a marker of neural differentiation, is widely observed in schwannomas. [4][5][6] Marked immunoexpression of S-100 protein was seen in the current case, confirming the neural derivation of the tumor.…”

“…Morphologically, schwannoma spindle-shaped cells are arranged in two distinct patterns, Antoni A and B, in variable proportions, with a few or none intralesional axons, forming completely encapsulated lesions. 5,6 The current case fulfills all the morphological criteria to be classified as schwannoma. It has also been highlighted that immunohistochemical positivity for S-100 protein, a marker of neural differentiation, is widely observed in schwannomas.…”

“…4 Local recurrence of schwannomas has not been reported after complete surgical excision of the tumors, and malignant transformation is exceptionally rare. 4,6 Although tumors of the peripheral nerve sheath are rare, they must also be included among the differential diagnoses of nodular lesions of the lower lip; 5 familiarity with morphological and immunohistochemical aspects of these lesions is essential to avoid diagnostic mistakes and provide a satisfactory therapeutic approach.…”

Palatal Schwannoma: An Analysis of 45 Literature Reports and of an Illustrative Case

“…From the included articles, clinical, histopathological, radiological, and treatment findings were charted ( Tables 1 and 2 ). 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54…”

“…Of the histological variant, the conventional subtype dominated and was reported in 40 cases (87%). It was followed by plexiform-3, 13 24 29 ancient-2, 32 49 and cellular variant- 1. 48 Almost all of the cases with conventional phenotype exhibited Verocay bodies and a predominance of Antoni A areas over Antoni B areas.…”