Ancient schwannoma of the parotid gland: A case report and review of the literature

Summary

Schwannomas are encapsulated benign tumours arising from nerve sheath cells, of which ancient schwannoma is one of five variants. Since the first description, only a few ancient schwannomas have been reported in different locations in the head and neck region. In the parotid gland, this tumour is very rare. In this report, a 41-year-old female patient with an ancient schwannoma of the parotid gland is presented and the data of this patient compared with other (comparable) cases described in the literature.

Introduction

Schwannoma (neurilemmoma) is an infrequent, benign, encapsulated tumour arising from nerve sheath cells (Conley, 1955). They are generally smooth and uniform in gross appearance and are usually surrounded by or attached to their nerve of origin (Toriumi et al., 1986). Although more commonly encountered in the extremities, approximately 25% of the cases originate from the neural structures of the head and neck region (Conley, 1955). In this region, schwannomas comprise a significant number of the tumours of the parapharyngeal space (Maniglia et al., 1979). Histologically, five variants of schwannomas have been described namely common, plexiform, cellular, epithelioid, and ancient schwannoma (Weiss and Goldblum, 2001).

The term ancient neurilemmoma was first suggested by Ackerman and Taylor (1951) in a review of 48 neurogenic tumours of the thorax. They reported 10 cases showed similar features of a typical neurilemmoma, but distinctive because significant portions of these tumours were composed of only few cells within a hyalinized matrix. They clarified that these features occurred in the schwannomas of long duration, and hence coined the term ‘ancient schwannoma’. This type is characterized by diffuse areas of hypocellularity, focal accumulations of hyaline material, and fatty degeneration (Eversole and Howell, 1971). In addition, thick capsules, relative absence of necrosis, and being usually infiltrated by large numbers of siderophages and histiocytes plus hyperchromatism are misleading in suggesting malignancy (Ackerman and Taylor, 1951).

Since that first report, a few authors described ancient schwannoma in a variety of locations in the head and neck region (Table 1). The parotid gland location of this tumour is very rare. To our knowledge there has only been one case reported of an ancient schwannoma of the parotid gland in the scientific literature (Jayaraj et al., 1997). In this report, a case of an ancient schwannoma of the parotid gland is presented, discussed, and the literature reviewed for head and neck location of this tumour.