Appendicular schwannoma Review of the literature on a rare benign tumor often mistaken for hyperplasia

Abstract

INTRODUCTION: Appendicular schwannoma is a rare benign neoplastic proliferation of the appendicular Schwann cells.

It is often asymptomatic until it occludes the appendicular lumen thus causing appendicitis-like symptoms.

EVIDENCE ACQUISITION. The neoplastic proliferation of the Schwann cells, although benign, may rarely degenerate into a malignant neoplasm, thus denoting the importance of diagnosis.

Some Authors in the Literature used the term “neuroma” or “neurinoma” to indicate either a hyperplastic proliferation of the Schwann cells or its neoplastic but benign proliferation, thus raising the important question of a probable mistaking of these two different histologic entities.

The hyperplastic proliferation is usually subsequent to a chronic appendicular inflammation, and it is a more common finding in specimen of appendectomy.

EVIDENCE SYNTHESIS: Aim of the study is to review the published scientific papers about the rare histologic entity of appendicular schwannoma and to define the not clear aspects of Schwann cell neoplasia versus hyperplasia. A review of the Literature from Medline/Pubmed has been accomplished. Forty-four studies from the Literature resulted suitable for our study.

CONCLUSION. Appendicular schwannoma has to be considered in patients with recurrent right lower quadrant pain, and may affect the patient’s prognosis if it remains undiagnosed, since it may degenerate in malignancy. There is a lack of clarity in the Literature about the distinction between the hyperplastic and the neoplastic benign Schwann cells proliferation, which must be clarified. The meaning of the terms “neuroma” and “neurinoma” should be standardized, the first referring to the hyperplastic proliferation, and the second to the neoplastic but benign proliferation of the Schwann cells.