Journal of Neuro-Ophthalmology, June 1983, Volume 3, Issue 2

Optic nerve sheath meningioma. Neuroradiologic findings.

Surgical exploration and biopsy confirmed the clinical diagnosis of bilateral optic nerve sheath meningiomas in a 27-year-old male patient with radiologic findings of calcifications of the intraorbital portions of the optic nerves. Plain orbital x-rays revealed ring calcifications and a CT scan disclosed the true extent of these calcifications, which were found to extend bilaterally along the nerves from the globes to the optic foramina. Coronal CT scan images revealed that the ring of calcification extended almost unbroken for the entire intraorbital length of the optic nerves. These optic nerve sheath calcifications represented calcified meningiomas.

]. Clin. Neuro-ophthalmol. 3: 85-89, 1983. Optic Nerve Sheath Meningioma Neuroradiologic Findings EDWARD M. COHN, MD. Abstract Surgical exploration and biopsy confirmed the clinical diagnosis of bilateral optic nerve sheath meningiomas in a 27-year-old male patient with radiologic findings of calcifications of the intraorbital portions of the op­tic nerves. Plain orbital x-rays revealed ring calcifica­tions and a CT scan disclosed the true extent of these calcifications, which were found to extend bilaterally along the nerves from the globes to the optic foram­ina. Coronal CT scan images revealed that the ring of calcification extended almost unbroken for the entire intraorbital length of the optic nerves. These optic nerve sheath calcifications represented calcified men­ingiomas. Introduction Calcification of the optic nerve sheath is a rare condition. It has been seen on CT scans as a curiosity by several observers. l After observing the patient presented in this article, a literature review of optic nerve sheath tumors since 1852 was con­ducted. A review led to the tentative, specific clin­ical diagnosis of optic nerve sheath meningiomas. This clinical evaluation was subsequently con­firmed histologically. This paper is meant to pre­sent this case and suggest a specific pathologic diagnosis based on radiologic findings. Case Report A 27-year-old male, with headaches dating back to childhood, presented with recent diplopia. His visual acuity was documented as being variable between 20/80 and 20/25 in each eye during the 4 months prior to neurosurgery. Neuro-ophthalmic findings included chronic pale swollen discs in addition to an atypical retinitis pigmentosa-like picture in each eye. (A more complete description is in preparation.) Radiologic studies prior to neurosurgical inter­vention included plain orbital films, which showed bilateral ring calcifications within the midportion of each orbit (Fig. 1). Skull films disclosed a mark- From the Neuro-ophthalmology Unit, Department of Ophthal­mology, William Beaumont Hospital, Royal Oak, Michigan. June 1983 edly enlarged sphenoid sinus with an upward ex­pansion evident in pneumosinus dilitans (Fig. 2). Axial CT scan disclosed bilateral calcification along the optic nerves intraorbitally (Fig. 3a). With atten­uation of the window-width, there appeared to be intracranial extensions of the calcifications through the optic foramina (Fig. 3b ), or more likely, hyper­ostosis of the lesser sphenoid wings. Optic foramen tomograms were interpreted as probably normal. Coronal CT scan disclosed ring calcifications rep­resenting almost complete bilateral encirclement of the optic nerves from the globe to the optic foram­ina (Figs. 4a and 4b). The diagnosis of calcified meningioma was con­firmed by biopsy taken at the time of right trans­frontal craniotomy with right optic foramen un­roofing. The left optic nerve was left undisturbed. Discussion The first recorded calcified optic nerve sheath tumor was by Critchett in 1852.2 Prior to the advent of diagnostic radiology, similar tumors were de­scribed by other surgeons and gross pathologists.a Subsequently, these optic nerve sheath tumors were further classified by microscopic patholog/ and found to be of two main types. The first was a fibrous nerve sheath tumor of almost cartillagen­ous consistency. The second main type was de­scribed as an endothelioma of the optic nerve sheath (presently classified as meningothelioma­tous meningiomas) containing laminated concre­tions (calcifications-psammoma bodies). Since earlier studies of the histology of these tumors, there have been numerous orbital and transcranial surgical approaches for these optic nerve sheath meningiomas. This has resulted in numerous path­ologic specimens and a retrospective history of the radiologic findings. Normal plain orbital x-rays and optic foramen views have been recorded previously"·6 in optic nerve sheath meningioma. Extension intracranially through the foramen could also be associated with normal x-rays of the head, orbits, and optic fora­men. 7 Plain films of the orbit and foramina have shown abnormalities in some cases. Intraorbital calcifications have been documented in the midor­bit H and in the orbital apex B - l1 1l0yd9 had five 85 Sheath Meningioma 86 Figure 1. Plain orbital films showing bilateral ring calcification (arrows). Figure 2. Pneumosinus dilitans seen on plain lateral skull film. Normally found at the level of the diaphragma sellae (small arrow), the roof of the sphenoid sinus is here found markedly elevated (heavy arrow). Journal of Clinical Neuro-ophthalmology Cohn Figure 3a. Axial CT scan demonstrates calcification along both optic nerves. Figure 3b. Window-width attenuation gives the impression of lesser sphenoid wll1g hypewstosis or intracranial extension of calcification. cases of optic nerve sheath meningioma in which there were radiographic changes on plain films in three cases; the changes consisted of an increase in the foraminal size in one case, calcification in the apex of the orbit in two cases, and calcification of the optic nerve sheath in two of the previously June 1983 mentioned cases. In documented unilateral optic nerve sheath meningiomas, plain films in some cases have demonstrated enlarged optic fora­mina. l~-17 In some cases of unilateral optic nerve sheath meningioma, with questionable intracranial involvement, foramen views have been found to be 87 Sheath Meningioma Figures 4a and 4b. Coronal views of the orbit disclose the almost unbroken ring of calcification around the optic nerves from the globe (a) through the central orbit (b) to the apex (not shown) bilaterally. normal."-7, 10, 17-20 Wrighe7 studied the x-ray find­ings in 27 cases over a 12-year period. All but two of the cases had normal x-ray studies; the two with positive findings had a slight increase in the size of the optic foramen. Bilateral optic nerve sheath meningiomas present a more insidious problem, and make interpretation of optic foramen views difficult, Even cases with intracranial extension through the foramina have been associated with "normal" x-rays of the foramina. 21 , 22 Occasionally, sphenoid ridge erosion has been noted with in- 88 creased optic foramen size in long-standing optic nerve sheath meningioma; Dunn2:J found this 17 years later in a patient followed for suspected tumor, Arteriography has been of some assistance, but has not always been able to confirm the presence of a mass or suggest the pathology.9,21 Uoyd9 has described five cases of optic nerve sheath menin­gioma with arteriography; he noted a minimal displacement of the ophthalmic artery in only one case, Orbital venography, not frequently utilized, Journal of Clinical Neuro-ophthalmo!ogy may show occlusion of an orbital vein 10; however, this is seen in various pathologic states. Pneumo­sinus dilitans24 seems to be either an associated or coincident finding in optic nerve sheath menin­gioma. Very few CT scan findings have been de­scribed in optic nerve sheath meningioma. WrigheS described thickening of the optic nerve in three of his five proven cases of optic nerve men­ingiomas. An additional casel7 several years later studied with coronal CT showed an enlarged optic nerve with central calcification. Other descriptions of optic nerve enlargement on CT have been men­tioned when horizontal cuts were used. 16.20.24 The radiologic findings on CT scan in this case and reported by Daniels 26 are strongly suggestive of the slow-growing optic nerve sheath meningioma. It is suggested that the radiologic diagnosis of optic nerve sheath meningioma could be made with certainty when the following are seen: 1) ring or incomplete ring calcification on plain orbital films; 2) calcification of the optic nerve on horizon­tal CT; and 3) ring or incomplete ring calcification around the optic nerve on coronal CT scan. Optic nerve tumors should be strongly suspected with optic foramen enlargement or optic nerve thick­ening on CT or orbital ultrasonography. Pneumo­sinus dilitans may raise suspicions. References 1. Trokel, S.L., Shults, W.T, and Sogg, R.L.: Personal communications. 2. Critchett: Medica/ Times and Gazette, V (New series, 1852, p. 465.) 3. Byers, W.GM.: The primary intradural tumors of the optic nerve. Stud. R. Victoria Hosp. Montrea/l­82, 1901. 4. Hudson, AC: Primary tumors of the optic nerve. K London Ophthalmol. Hosp. Rep. 18: 317-439,1912. 5. Coston, TO.: Primary tumor of the optic nerve. Arch Ophthalmol. 15: 696-702, 1936. 6. Edwards, TS., and Finlay, I.R.: Meningioma of the optic nerve. Am. I. Ophthalmol. 46: 745-747, 1958. 7. Love, I.G, and Rucker, CW.: Meningioma of the sheath of the optic nerve. Arch Ophthalmol. 23: 377-380,1940. 8. Hannesson, O.B.: Primary meningioma of the orbit invading the choroid. Acta Ophthalmol. 49: 627­632,1971. 9. Lloyd, GAS.: The radiology of primary orbital men­ingioma. Br. I. Radiol. 44: 405-411,1971. 10. Takahashi, M., Lombardi, G, Passerini, A, and Ohno, S.: Primary intraorbital meningiomas: A roentgenologic study. Neuroradi%gy 5: 95-101, 1973. 11. Rusu, M., Stanciu, A, Sandulescu, Gh., and Costa­chescu, G.: Meningioma of the optic nerve in chil­dren- Considerations on 2 cases. Rev. Chir. 23: 231­234, 1979. 12. Ryan, H.: Intraorbital meningioma of the optic nerve. Br. I. Ophthalmol. 37: 506-507, 1953. 13. Ardouin, M., Pecker, J., Stabert, Ch., Catros, A, and June 1983 Cohn Javalet, A: Meningioma of the optic canal in a 7 year old boy (Paris). Rev. Otoneuroophtha/mol. 30: 486-489, 1958. 14. Spencer, W.H.: Primary neoplasms of the optic nerve and its sheaths: Clinical features and current concepts of pathogenetic mechanisms. Trans. Am. Ophthalmol. Soc. 70: 490-528, 1972. 15. Shuangshoti, S.: Meningioma of the optic nerve. Br. I. Ophthalmol. 57: 265-269, 1973. 16. Zakka, K.A, Summerer, R.W., Vee, RD., Foos, R.Y., and Kim, J.: Opticociliary veins in a primary optic nerve sheath meningioma. Am. I. Ophthalmol. 87: 91-95, 1979. 17. Wright, J.E., Call, N.B., and Liaricos, S.: Primary optic nerve meningioma. Br. I. Ophthalmol. 64: 553­558, 1980. 18. Loisillier, F., and Bernard, P.: Two cases of menin­gioblastoma of the optic nerve (France). Bull. Soc. Ophtha/mol. 2: 175-177, 1959. 19. Sood, GC, Malik, S.K.R., Gupta, O.K., and Gupta, AN.: Bilateral meningiomas of the orbit. Am. I. Ophthalmol. 61: 1533-1535, 1966. 20. Susac, J.O., Smith, J.L., and Walsh, F.B.: The impos­sible meningioma. Arch. Neurol. 34: 36-38, 1977. 21. Hollenhorst, R.W., Jr., Hollenhorst, KW., Sr., and MacCarty, CS.: Visual prognosis of optic nerve sheath meningiomas producing shunt vessels on the optic disk: The Hoyt-Spencer syndrome. Trans. Am. Ophthalmol. Soc. 75: 141-163, 1977. 22. Hart, W.M., Jr., Burde, R.M., Klingele, TG, and Perlmutter, J.C: Bilateral optic nerve sheath menin­giomas. Arch. Ophthalmol. 98: 149-151, 1980. 23. Dunn, S.N., and Walsh, F.B.: Meningioma (dural endothelioma) of the optic nerve. Arch. Ophthalmol. 56: 702-707, 1956. 24. Hirst, L.W., Miller, N.R., Hodges, F.J., Corbett, J.J., and Thompson, H.S.: Sphenoid pneumosinus dili­tans- A sign of meningioma originating in the optic canal. Neuroradiology 22: 207-210, 1982. 25. Wright, J.E.: Primary optic nerve meningiomas: Clin­ical presentation and management. Trans. Am. Acad.Ophthalmol. 83: 617-625, 1977. 26. Daniels, D.L., Williams, AL., Syvertsen, A, Gager, W.E., and Harris, GJ.: CT recognition of optic nerve sheath meningioma: Abnormal visualization. Am. I. Neuroradiol. 3: 181-183, 1982. Acknowledgments The author thanks Paul Fecko, MD. (Birmingham, Michigan), for referring this case; Dave Edds (M.CT Associates, Southfield, Michigan), for technical assist­ance with CT; and Harvey I. Wilner, MD. (Associate Professor of Neuroradiology, Wayne State University School of Medicine, Detroit, Michigan), for helping se­lect films for publication. Write for reprints to: Edward M. Cohn, MD., Neuro­Ophthalmology Unit, Department of Ophthalmology, William Beaumont Hospital, 3601 West 13 Mile Road, Royal Oak, Michigan 48072. 89