Meningioma

Abstract

Meningioma is a well-recognized tumor of the central nervous system, but it rarely appears as a primary extra-cranial tumor of the paranasal sinuses. We report a case of a primary right anterior ethmoid meningioma that resembled a mucocele in its presentation. A primary meningioma can be differentiated from a secondary meningioma in three ways: (1) by observing an intact bony wall of the sinus on imaging or on inspection during surgery, (2) by noting the absence of a simultaneous intracranial meningioma on imaging or on inspection during surgery, and (3) by identifying a bulging of the sinus wall toward the cranium rather than in the opposite direction.

Introduction

Meningiomas account for nearly 20% of all intracranial neoplasms, and they are the second most common tumors of the central nervous system (following gliomas). Primary meningiomas of the paranasal sinuses are extremely rare. To date, only 30 cases have been previously described in the English-language literature. (1) In this article, we describe a new case of primary extracranial meningioma that occurred in the right anterior ethmoid sinus and that resembled a mucocele in its presentation.

Case report

A 20-year-old woman was admitted to our hospital with a chief complaint of a facial deformity that had arisen 1 year earlier. Her right eye was proptotic and deviated to the inferolateral side. Her visual acuity, visual field, and range of motion were normal. She denied diplopia, nasal obstruction, postnasal drip, nasal discharge, and a history of trauma to her head or face. She did relate a history of transient and intermittent right-sided headache. Her history also included a cesarean section 1 year earlier.

Findings on physical examination of her mouth, nose, pharynx, larynx, ears, cranial nerves, and neck were normal. Axial and coronal computed tomography (CT) of her face revealed the presence of an expansive mass in the right anterior ethmoid sinus, with nonhomogeneous density in its upper portion (figure). The bony walls of the affected anterior ethmoid sinus were thickened, sclerotic, and pushed outward. No communication with cranium was seen.

After the patient was administered intravenous sedation and local anesthesia, the mass was biopsied under endoscopic visualization. Pathologic study of the specimen confirmed a diagnosis of transitional meningioma with psammoma bodies. Via a frontal extradural craniotomy approach, we exposed the bony wall of the right anterior ethmoid sinus, which had bulged toward the frontal space of the cranium. The bony wall of the ethmoid sinus that faced toward the cranium was completely intact. The sinus was opened, and the tumor was removed. Reconstruction of the medial wall of the right orbit was performed at the same time.

At the 14-month follow-up, the patient was symptom-free and exhibited no evidence of recurrence.

Discussion

Meningiomas arise from meningothelial arachnoid cells, which are derived from the neuroectoderm. Nevertheless, meningiomas are usually classified as mesodermal tumors. (2) The most common histologic classification of these tumors is based on the predominant cell type, and it includes five groups:

* Syncytial (meningotheliomatous, endotheliomatous) tumors feature cells that replicate the normal appearance of arachnoid cap cells, and they contain prominent cellular whorls and nodules.

* Fibroblastic (fibrous type) tumors feature spindle-shaped bipolar cells that resemble fibroblasts and contain bands of collagen.

* Transitional or mixed tumors are characterized by a whirling pattern of somewhat spindly elements, and they often contain psammoma bodies.

* Angioblastic tumors are cellular and rich in capillary blood vessels.

* Sarcomatous (malignant) tumors are exceedingly rare.

Transitional meningiomas are the most common of these tumors (75% of cases), followed by syncytial and fibrous tumors (10% each), angioblastic tumors (5%), and sarcomatous tumors (<1 %). (3) Our patient had a transitional meningioma.

In the head and neck area, apparently primary extracranial meningiomas have been described in the skull bones, orbit, scalp, temporal bone, middle ear, nasal cavity, and paranasal sinuses, but such cases are rare. (4) Extracranial meningiomas are classified as one of four types (5):

* An extracranial extension of a meningioma with an intracranial origin.

* An extracranial extension of a meningioma arising in a neural foramen.

* An ectopic and primarily extracranial meningioma without connection with either the foramen of a cranial nerve or the endocranium.

* An extracranial metastasis from an intracranial meningioma to a parapharyngeal lymph node.

By far, the most common type is an extracranial extension of an intracranial meningioma.

Three criteria can help the otolaryngologist differentiate a primary from a secondary sinus meningioma:

* An intact bony wall of the sinus observed on imaging or on inspection during surgery.

* The absence of a simultaneous intracranial meningioma observed on imaging or on inspection during surgery.

* A bulging of the sinus wall toward the cranium rather than in the opposite direction.

In our patient, all three criteria were present. Distinguishing between a meningioma of the paranasal sinuses and another condition--such as mucocele, mucopyocele, sinusitis with osteomyelitis, and fibrous dysplasia--is extremely difficult. Surgical excision is the modality of choice for treating these tumors. These lesions do not appear to respond well to radiation, so radiotherapy probably should be reserved only for those patients in whom surgical resection has not been successful. (4)

References

(1.) Brunori A, Scarano P, Colacecchi R, Chiappetta F. A case of primary meningioma of the frontal sinus. Neurochirurgie 1999;45:307-11.

(2.) Rubinstein LJ. Atlas of Tumor Pathology. Washington, D.C.: Armed Forces Institute of Pathology, 1972.

(3.) Lumsden CE. Tissue culture in relation to tumors of the nervous system. In: Russell DS, Rubinstein LJ, eds. Pathology of Tumors of the Nervous System. 5th ed. London: Arnold, 1989:130-5.

(4.) Perzin KH, Pushparaj N. Nonepithelial tumors of the nasal cavity, paranasal sinuses, and nasopharynx. A clinicopathologie study. XIII: Meningiomas. Cancer 1984;54:1860-9.

(5.) Nager GT, Heroy J, Hoeplinger M. Meningiomas invading the temporal bone with extension to the neck. Am J Otolaryngol 1983;4:297-324.

From the Department of ENT (Dr. Daneshi and Dr. Asghari) and the Department of Neurosurgery (Dr. Bahramy). Hazrat Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran.

Reprint requests: Alimohamad Asghari, MD, Department of ENT, Hazrat Rasoul Akram Hospital, St. Niayesh, Ave. Satarkhan, Tehran, Iran. Phone: 98-216-017-151; fax: 98-216-511-011; email: entdepar@hbi.or.ir or farshadmd@hotmail.com

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