Extracranial Schwannomas of the Head and Neck: A Literature Review and Audit of Diagnosed Cases Over a Period of Eight Years.

Abstract

Schwannoma is a benign, slow growing, usually solitary and encapsulated tumor derived from Schwann cells of the nerve sheath. Schwannomas can be divided into central, or intraosseous, and peripheral lesions. The etiology is unknown, but it is postulated that lesions arise by the proliferation of Schwann cells at one point inside the perineurium. Schwannomas may mimic other diseases of the head and neck, such as infection, tumor ormetastasis. Extracranial schwannomas are rare; in this study we review a series of 22 cases of schwannomas originating in the head and neck region over a period of eight years. All tumors were benign and well-encapsulated. Tumor size ranged from 0.5 to 9cm.The age range of patients studied was 15-74years with a mean age of 35 yearsand a male predilection (M:F, 2.6:1)was noted. Four cases ofschwannomas occurred in thetongue (18.18%)and lower lip(18.18%), three in the nasal cavity(13.64%), twoeach (9.09%)in thebuccal mucosa, parapharyngeal space(9.09%), and eyebrow(9.09%), and one eachin the upper lip(4.55%), lateral canthus of the eye(4.55%), intraorbital region(4.55%), submandibular gland(4.55%), and ear(4.55%). Schwannomas can present in a wide variety of sites within the head and neck. The tumor is benign and tend to be asymptomatic for long periods of time. Histopathology is the gold standard for diagnosis.Our study describes the clinicopathologic features of extracranial head and neck schwannomas, highlights the histopathologic features, and discusses pertinent findings with correlation to the present literature. It is important that both clinicians and pathologists be familiar with theuncommon sites of occurrenceand the potential pitfalls associated with the diagnosis and management of these tumors.