Primary optic nerve meningiomas rarely present with pain. Pain was noted in none of 47 patients in one series (1) and in 2 of 50 in another (2). Judging from the paucity of published examples, other symptoms or signs of inflammation in patients with primary optic nerve meningiomas are also exceptions at any stage in their course.
We report a man with a biopsy-proven primary optic nerve meningioma of the secretory type in whom episodes of striking clinical signs of inflammation first developed 9 years after orbital surgery and radiation coincident with imaging evidence of tumor growth. Yet histopathologic examination of rebiopsy specimens failed to show signs of inflammation.
In November 1993, a 28-year-old man noticed a blur in the temporal field of his left eye and gaze-induced amaurosis of that eye. Four months later, slight pain in the left eye and temple supervened. Visual acuity was 20/20 in the right eye and the examination of that eye was completely normal apart from myopia. Visual acuity was 20/25 in the left eye with slight ptosis, but no lid erythema or edema was present. On the left, there was 4 mm of proptosis, a tight but non-tender orbit, an area of bulbar conjunctival congestion temporally, a relative afferent pupil defect, a full visual field, omnidirectional ophthalmoparesis, and an edematous optic disc.
MRI showed an enhancing intraconal tumor occupying almost the entire left orbit but sparing the optic canal. At lateral orbitotomy for biopsy, the tumor appeared to arise from the nerve sheath immediately behind the globe. The surgeon commented that there appeared to be so much inflammation surrounding the tumor that dissection proved difficult. Histopathologic examination showed that the tumor was a benign meningioma. There were no histopathologic signs of inflammation.
Except for a persistently dilated pupil, the patient incurred no new deficits from the surgery. Postoperatively, he received radiation consisting of a combination of megavoltage x-ray and proton beam to a total dose of 59.4 cobalt Gray equivalents. Six months later, visual acuity in the left eye had improved to 20/15, there was no ptosis and only 1 mm of proptosis, and the optic disc edema had cleared without the development of optic disc pallor. The eye movements remained reduced in all directions in the left eye.
One year after completing radiation therapy, he developed pain in the left inner canthal region. Visual acuity was 20/25 in the left eye, and there was an inferonasal visual field defect and slight optic disc edema. MRI showed considerable shrinkage of the tumor compared with the study after orbitotomy. Pain and optic disc edema recovered spontaneously after several weeks. Six months later, there was a more extensive visual field defect, an area of congestion of the nasal segment of the bulbar conjunctiva, and optic disc pallor. MRI showed no changes relative to the study performed 6 months earlier.
He had no further symptoms until 9 years after the orbital surgery, when he rapidly developed pain and tenderness of the left orbit with ptosis, lid swelling, 4 mm of proptosis, and a drop in visual acuity in the left eye to 20/50. MRI showed that the tumor had enlarged, but the paranasal sinuses and cranial contents were normal. Diagnoses of idiopathic orbital inflammation (IOI) and malignant transformation of the tumor were considered.
He was treated with 60 mg/day prednisone. Within 12 hours, the pain and tenderness had virtually disappeared. He was successfully weaned from the prednisone over 3 weeks, and all abnormal findings disappeared.
One year later, pain recurred in the left superior sulcus, soon involving the eye and periorbital region. Visual acuity had again fallen to 20/50. There was 5 mm of proptosis, nontender swelling of the upper and lower lids, and edema of the bulbar conjunctiva (Fig. 1). Imaging showed further enlargement of the tumor, which was now extending through the lateral wall of the orbit at the site of the lateral orbitotomy (Fig. 2). Symptoms again resolved rapidly with oral prednisone therapy (60 mg for 2 days followed by doses tapered over 3 weeks), but he only regained 20/40 visual acuity.
The patient remained stable for 6 months, when he developed slight pain in the left temple and lid swelling. Visual acuity was 20/200, and there was lid edema and congestion of the bulbar conjunctiva. MRI showed further enlargement of the tumor. The symptoms and signs again improved with 60 mg prednisone for 2 days followed by doses tapered over 3 weeks only to return when the prednisone therapy was stopped. Several days of 60 mg/day oral prednisone failed to alleviate the pain and swelling.
Eleven years after the original orbital surgery, the tumor was again surgically debulked. Histopathologic examination showed a benign meningioma infiltrating the extraocular muscles. There were no signs of inflammation. However, the tumor had features of a secretory meningioma (Fig. 3). Two years after the second orbital surgery, he developed a recurrence of left orbital pain and lid swelling that was reversed with oral prednisone therapy.
Our patient had periocular pain as a presenting symptom of a benign optic nerve sheath meningioma. He suffered multiple episodes of more severe periocular pain, together with signs of orbital inflammation and lid edema after biopsy and radiation treatment. Nine years after these interventions, he manifested signs resembling IOI. MRI showed tumor enlargement.
In 1992, Wroe et al (3) reported two patients who had pain associated with primary optic nerve sheath meningioma. One was a 47-year-old woman with extradural extension of a primary optic nerve sheath meningioma who had periocular pain and ipsilateral headache before any visual loss. The second was a 37-year-old woman with an orbital apex meningioma whose first symptom was pain and who was originally thought to have IOI. She improved with corticosteroid treatment. The authors did not comment on the presence or absence of histopathologic signs of inflammation in the biopsied tissue. We have not found other reported examples.
In our patient, the original surgeon commented that there were gross signs of inflammation around the tumor, but histopathologic evidence of inflammation was not present in the microscopic sections. Similarly, examination of the tissue obtained at the subsequent debulking showed no inflammation.
Inflammatory meningiomas, of which few examples have been documented, contain plasma cell-lymphocytic components [lymphocyte-rich meningioma (LRM)], which were absent in our patient (4). Radiation treatment of tumors may cause necrosis with attendant inflammation. However, the long interval (9 years) between the completion of therapy and the development of inflammatory symptoms and signs makes it unlikely that radionecrosis was responsible. When orbital inflammation occurs spontaneously from tumors, the tumors are typically malignant, and necrosis is often the mechanism. Our patient's lesion was histopathologically benign, and necrosis was not seen in the sections. There was radiologic evidence of tumor enlargement at the time of two of the episodes, which suggests that the changes might have represented a reaction to tumor expansion. However, the fact that long asymptomatic periods followed short courses of corticosteroid treatment, during which there may have been continuing tumor growth, together with the fact that an episode occurred in association with shrinkage of the tumor, suggests that tumor growth may not be the entire explanation.
Another possibility is that the episodes were related to the subtype of the meningioma. Secretory meningiomas are rare, tend to occur over the frontal convexities or sphenoid ridge, and are often attended by brain edema. The episodes in our patient might have been triggered by edema (5).
Clinicians should be aware that benign primary optic nerve meningiomas may, albeit rarely, cause episodic symptoms resembling those of IOI that resolve with corticosteroid treatment.
1. Jakobiec FA, Depot MJ, Kennerdell JS, et al. Combined clinical and computed tomographic diagnosis of orbital gliomas and meningiomas. Ophthalmology
2. Wright JE, McNab AA, McDonald WI. Primary optic nerve meningioma. Br J Ophthalmol
3. Wroe SJ, Thompson AJ, McDonald WI. Painful intraorbital meningiomas. J Neurol Neurosurg Psychiatry
4. Horten BC, Urich H, Stefoski D. Meningiomas with conspicuous plasma cell-lymphocytic components: a report of five cases. Cancer
5. Buhl R, Hugo HH, Mihalovic Z, et al. Secretory meningiomas: clinical and immunohistochemical observations. Neurosurgery
© 2007 Lippincott Williams & Wilkins, Inc.
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