Fine-needle aspiration cytology of a primary ectopic meningioma.

Meningiomas are benign tumors derived from arachnoid cells. Most commonly an intracranial lesion, meningiomas may be found extracranially in various anatomic sites. A 23-yr-old white female presented with left-sided palpable mass located submucosally in the floor of the mouth. CT scan revealed no evidence of mass elsewhere in the head and neck region. Fine-needle aspiration cytology (FNAC) showed loose and cohesive cellular fragments with lobular growth pattern and uniform round or ovoid cells. The diagnosis of low-grade salivary gland neoplasm, not further classified, was made. The tumor was locally excised. The differential diagnoses of an extracranial meningioma and pleomorphic adenoma were discussed at the frozen section. Based on light microscopic, immunohistochemical, and electron microscopic (EM) findings, the final diagnosis of an ectopic meningioma was rendered. Ectopic meningiomas may pose a diagnostic challenge to clinicians and cytopathologists. It is easily forgotten in the list of differential diagnosis at an ectopic site. Primary ectopic meningioma in a region containing salivary gland(s) may mimic benign and low-grade malignant salivary gland tumors in FNAC. Copyright 2002 Wiley-Liss, Inc.