Extracranial sinonasal tract meningiomas: a clinicopathologic study of 30 cases with a review of the literature.

Extracranial meningiomas of the sinonasal tract are rare tumors. These tumors are frequently misclassified, resulting in inappropriate clinical management. To date, there has been no comprehensive study to evaluate the clinicopathologic aspects of meningioma in these anatomic sites. Thirty cases of sinonasal tract meningiomas diagnosed between 1970 and 1992 were retrieved from the files of the Otorhinolaryngic Registry of the AFIP. Histologic features were reviewed, immunohistochemical studies were performed, patient follow up was obtained, and the results were statistically analyzed. The patients included 15 females and 15 males, aged 13 to 88 years (mean, 47.6 yrs). Patients presented clinically with a mass, epistaxis, sinusitis, pain, visual changes, or nasal obstruction, dependent on the anatomic site of involvement. Symptoms were present for an average of 31.1 months. The tumors affected the nasal cavity (n = 14), nasopharynx (n = 3), frontal sinus (n = 2), sphenoid sinus (n = 2). or a combination of the nasal cavity and ethmoid, frontal, sphenoid, and/or maxillary sinuses (n = 9). The tumors ranged in size from 1.0 to 8.0 cm in greatest dimension (mean, 3.5 cm). Radiographic studies demonstrated a central nervous system connection in six cases. The tumors often eroded the bones of the sinuses (n = 18) and involved the surrounding soft tissues, the orbit, and occasionally the base of the skull. Histologically, the tumors demonstrated features similar to intracranial meningiomas. The majority were of the meningothelial type (n = 23), although there were three atypical meningiomas. Immunohistochemical studies confirmed the diagnosis of meningioma with positive reactions for epithelial membrane antigen (EMA) and vimentin (all tested). The differential diagnosis includes paraganglioma, carcinoma, melanoma, psammomatoid ossifying fibroma, and angiofibroma. Surgical excision was used in all patients. Three patients died with recurrent disease (mean, 1.2 yrs), one was alive with recurrent disease (25.6 years), and the remaining 24 patients were alive or had died of unrelated causes (mean, 13.9 yrs) at the time of last follow up (two patients were lost to follow up). Extracranial sinonasal tract meningiomas are rare tumors which need to be considered in the differential diagnosis of sinonasal tumors. A whorled growth pattern and psammoma bodies, combined with positive EMA and vimentin immunohistochemical reactions, can confirm the diagnosis of meningioma. The overall prognosis is good, without a difference in outcome between benign and atypical meningiomas.