Clin.Radiol. (1979) 30, 105-110

The Radiology of Orbital Meningioma pETER MACPHERSON From the Department o f Neuroradiology, Institute o f Neurological Sciences, Southern General Hospital, Glasgow G51 4TF During a five-year period three patients with primary and 14 with secondary orbital meningiomas were examined- The appearances seen on plain films, subtraction angiography, venography, scintiscan and EMI scan are described and compared. Plain films were abnormal in 13 of the 17 cases and this was the investigation which most frequently suggested the diagnosis. Arteriograpkic abnormalities were present within the orbit in 12 of the 16 cases so examined, an actual tumour blush occurring in 6/16. Venography showed evidence of the lesion in 12/14;in two cases it was the only investigation to give positive findings. Abnormality in the adjacent cavernous sinus was demonstrated in 6/13. Scintiscan was negative in the one primary case examined; it showed evidence of the intracranial lesion in the seven secondary cases examined but could not demonstrate intraorbital extension. The orbital lesion would have been demonstrated in all cases without the use of computed tomography but the delineation of the lesion was seen more clearly on the EMI scan in 12/14 than by other methods of investigation. Neither the density of the lesion nor the increase of attenuation after contrast was helpful in suggesting the diagnosis. A combination of plain and contrast radiology with computed tomography is recommended with a view to increasing the diagnostic accuracy and determining the full extent of a lesion. Intracranial investigation is required also, where an orbital space occupying lesion is suspected and orbital examination should be done when an intracranial peri-orbital meningioma is diagnosed. A case history is given to show how the various investigations may complement each other.

A meningioma in the orbit may have arisen there as a primary lesion or be the result of extension of an intracranial tumour. Leber (1877) differentiated primary meningiomas into those arising within the dural sheath of the optic nerve and those taking origin in the outer sheath or attached to the latter. Craig and Gogella (1949) subdivided sheath meningiomas into those arising within the optic canal and those taking origin within the orbit. They labelled as extradural, lesions which did not originate from the nerve sheath but lay either within or outside the muscle cone, or were attached to the peri-orbita. In the largest series on record (25 cases collected from two centres over 43 years) Karp et al. (1974) were unable to find a case in which the meningioma had originated within the orbit but outside the meningeal sheath of the optic nerve. We have classified secondary orbital meningiomas into those spontaneously invading the orbit; where the orbital cavity has simply been reduced by hyper0stotic reaction;and to post-operative invasion. This survey is of the five-year period 1973-77, more or less coinciding with the advent in the Institute of Neurological Sciences of the EMI scanner, orbital venography and subtraction arteriography. Based on paper read at meeting of the Scottish Association of NeurologicalSciences, Glasgow, 1978.

9

MATERIAL Incidence. During the survey period, 114 patients had cranial meningioma. In 111 cases, the lesion arose primarily within the skull and in 14 of these there was secondary involvement of the orbit. In three, :the lesion originated within the orbit. The three primary orbital meningiomas arose from the nerve sheath, one in the foraminal region and the other two more peripherally. Of the 14 secondary cases, 12 arose from the sphenoid wing and two subfrontally. In eight there was spontaneous invasion, six via the bony walls and two via the optical canal. Hyperostotic reaction narrowing the orbit was present in two cases. Post-operative invasion via the bony walls occurred in four cases. There were 30 patients with sphenoid wing meningioma, 12 of whom had orbital involvement as had two of the eight subfrontal cases. The ages of the primary cases were 34, 38 and 60. The average age of the patients with sphenoid meningiomas without orbital involvement was 51, whereas with orbital involvement it was 55. Presentation. Fifteen of the 17 cases had proptosis. One of the three primary cases was referred intially for intracranial investigation and four of the 10 secondary cases with spontaneous invasion or hyperostotic narrowing of the orbit were sent as probable orbital space occupying lesions. The 11 cases

106

CLINICAL RADIOLOGY

with involvement of the optic nerve, either primarily or secondarily, had diminished visible acuity, leading in seven cases to blindness. RADIOLOGY Plain Film Appearances. Positive change was seen in one of the three primary cases, the abnormality being erosion and enlargement of the orbit. In the secondary group, 13 of the 14 had evidence of abnormality. Singly, or in combination with other bone change, eight had sclerosis of the lesser wing of the sphenoid; seven of the greater; erosions were present in four; three had sclerosis of planum sphenoidale; two had orbital enlargement and two widening of the optic canal; one had narrowing of the superior orbital fissure. Contrast Orbitography and Pneumography. These examinations were not used as both have lead to permanent blindness. Arteriography. In the primary group, two showed intraorbital abnormality; one with stretched vessels and the other showed a tumour blush. There was no evidence of intracranial abnormality. In the secondary, 10 of the 13 examined had intracranial abnormalities. All 10 had displaced vessels and tumour blush was present in seven. Similarly, 10 of the 13 had intraorbital vessel displacement, five of which had blush. Venography. Abnormalities were present in the three cases in the primary group. One had displacement and obstruction; one had displacement alone and one obstruction alone. Further, in one, the anterior half of the cavernous sinus was shown to be involved by extension of the tumour through the optic canal. In the secondary group, nine of the 11

examined had intra-orbital abnormalities. Five had displacement and obstruction; two had displacement alone and two obstruction alone. The cavernous sinus was noted to be involved in five of the 10, by displacement and/or non-filling. Scintiscan. This examination was performed in only one of the three primary cases and was negative. In the seven secondary cases examined it showed evidence of the intracranial lesion. E M I scan. This examination was performed on two of the patients in the primary group and was positive in both. There was no evidence of intra. cranial extension. In the secondary group it was positive in 10 out of 12 who had orbital scans though one of the negatives was done with the earlier matrix. In nine out of the 13 who had intracranial cuts, there was evidence of the intracranial abnormality. Of the four postoperative cases, all showed positive EMI appearances within the orbit while only two had evidence of intracranial abnormality, suggesting that in two the operation had dealt satisfactorily with the intracranial component. Density. Two measurements in EMI units were taken in each case; the average density and the highest density in the lesion. The range of the average densities was 5-45, the mean of these being 24. The range of highest densities was 15-60 (mean 39). These estimations were repeated on the post-contrast scans. In each case 50ml of meglumine iothalamate 420 was used for enhancement. The range of average densities was 1 5 - 6 0 (mean 33.5). The range of highest densities was 3 0 - 8 0 (mean 49.5). The increase of average density after contrast ranged from 0 to 20 (mean 9.5), while the increase of highest density ranged from 0 to 20 (mean 10.5).

Table 1 - Summaryof the investigation results as they relate to the orbit elQin

film abnormal

Primary (3) Secondary Spontaneous invasion (8) Hyperostotic reaction (2) Post-op invasion (4) (14)

Angiogram

Venogram

Abnormal Displaced Blush vessel

Abnormal Displaced Obstructed vessel

Scin tiscan EM[ scan abnormal abnormal

1/3

2/3

1/3

1/3

3/3

2/3

2/3

0/1

2/2

8/8

7/8

7/8

5/8

6/7

5/7

4/7

0/4

6/8

2/2

1/2

1/2

0/2

1/2

1/2

1/2

0/2

0/0"

3/4

2/3

2/3

0/3

2/2

1/2

2/2

0/1

4/4

13/14

10/13

10/13

5/13

9/11

7/11

7/11

0/7

10/12

* Orbital cuts had not been taken.

RADIOLOGY OF ORBITAL MENINGIOMA

107

Table 2 - Summary of the investigation results as they relate to the intracranial region Angiogram Abnormal

primarY (3) Secondary Spontaneous invasion (8) l-lyperostotic reaction (2) Fost-op invasion (4) (14)

Cavernous sinogram Displaced vessel

Blush

Abnormal

Displdced

Non-filling

Scin tiscan abnormal

EMI scan abnormal

0/3

0/3

0/3

1/3

0/3

1/3

0/1

0/2

7/8

7/8

5/8

3/7

2/7

2/7

4/4

6/8

2/2

2/2

2/2

0/1

0/1

0/1

2/2

1/1

1/3

1/3

0/3

2/2

0/2

2/2

1/1

2/4

10/13

10/13

7/13

5/10

2/10

4/10

7/7

9/13

Table 1 shows a s u m m a r y of t h e investigation results as t h e y relate to the orbit and Table 2 the intracranial findings.

CASE REPORT A case demonstration will show how the various diagnostic procedures may complement one another. A female aged 56 was sent for examination, the referral card stating, 'Right proptosis for many years, ?tumour in orbit'. The plain films demonstrated hyperostosis of the planum sphenoidale, across to the righf posterior orbital wall where the optic canal was widened (Fig. 1). EMI scan showed evidence of a retroglobal space occupying lesion which extended forwards

to overlap slightly the globe (Fig. 2). There was a large area of reduced density on the right suggesting middle cerebral artery infarction, On enhancement there seemed to be evidence of an intracranial component though this was less definite on measure prints (Fig. 3). Venography demonstrated an intraconal space occupying lesions (Fig. 4). Anglography demonstrated elevation of the ophthalmic artery with downward looping of the ciliary branches (Fig. 5), These latter findings have to be considered in association with the plain film changes from which one might have expected a superiorly placed space occupying lesion! Intracranially the distal internal carotid artery was narrowed and the middle cerebral artery occluded. Fig. 6 shows the operative findings: the lesion arose from the planum sphenoidale, stretched the left optic nerve, destroyed the right, occluded the right

Fig. 1 - Hyperostosis of right posterior orbital wall with widening of optic canal

108

CLINICAL RADIOLOGY

Fig. 2 - EMI scan showing a retro-~obal mass which extends forward to overlap slightly the globe. The large area of reduced attenuation suggests right middle cerebral artery infarction.

Fig. 3 - Enhanced scan showing increased attenutation in the suprasellar region, adjacent to the planum sphenoidah and anterior clinoid processes, and extending laterally on the right.

Fig_ 4 -Venography demonstrating an intraconal space occupying lesion.

Fig. 5 - Arteriography demonstrating elevation of the ophthalmic artery with downward looping of ciliary branches.

middle cerebral artery and extended through the optic canal in dumb-bell fashion.

accounted for 5 - 1 0 % o f expanding lesions in the orbit that produced unilateral exophthalmos. During our survey period, 82 patients with unilateral proptosis were examined. A verified diagnosis was obtained in only 54 cases, three of wtgch had primary and 12 secondary orbital meningiomas. Craig and Gogella (1949) reported that 39% of their sphenoid wing meningiomas had orbital involve. m e n t as had 30% o f the subfrontal cases. Our own figures o f 40 and 25% respectively are similar. Age. Walsh (1970) reported that sheath menin. gioma could occur at any age but was more common in children than were intracranial lesions. Karp et d, (1974) reported that in their series, 40% of patients with primary orbital meningiomas were under the age o f 40. In the present series two of the primary cases were under the age of 40. No literature can be traced

DISCUSSION Takahashi et al. (1973) noted that there was very little information in the literature relating intracranial to orbital meningiomas. Cushing and Eisenhardt ( 1 9 3 8 ) r e p o r t e d that during a period when 313 intracranial meningiomas were recorded only one had originated in the orbit. Lombardi (1967) encountered five cases in a series in which 613 intracranial meningiomas occurred. In the present series there were three orbital to 111 intracranial meningiomas. Karp et al. (1974) stated that the exact incidence of primary intra-orbital meningiomas was unclear but in general probably

RADIOLOGY

OF ORBITAL

A D

~

C

K

tI

G k. site of origin of tumour

I~, C, D. E. F,

ophthalmic Art. optie canal Turaour Lt. Internal Carotid Artery Lt. optic nerve

G. Pituitary stalk H, Rt. Anterior Cerebral Artery I. Hr. Middle C e r e b r a l A r t e r y J.

Hr. optic nerve

K. Tentoriurn

Fig. 6. - R e c o n s t r u c t i o n o f o p e r a t i v e findings. T h e l e s i o n arose f r o m t h e p l a n u m s p h e n o i d a l e , s t r e t c h e d t h e l e f t o p t i c nerve, d e s t r o y e d the right, o c c l u d e d the r i g h t m i d d l e c e r e b r a l artery a n d e x t e n d e d t h r o u g h t h e o p t i c canal in d u m b - b e l l

fashion. regarding sphenoid wing and subfrontal lesions comparing the ages of those with and without orbital involvement. In the Institute series, sphenoid wing cases with orbital involvement were on average older than those without. Radiology. In 1949 Craig and Gogella reported that 65% of primary orbital meningiomas showed no abnormality on any X-ray examination whereas over 90% were positive in the secondary group. Techniques have improved and by 1971 Lloyd showed evidence of space occupying lesion in seven out of eight primary meningiomas. In this Institute series, even without the use of computed tomography, radiological examination showed evidence of the disease in all primary and secondary cases. Plain Films. Susac et al. (1977) reported that all three of their primary cases showed no plain film abnormality. In other series, abnormalities have been noted as follows: Henderson (1973) 4 of 14; Craig and GogeUa (1949) 6 of 17; Takahashi et al. (1973)4 of 6; Lloyd (1971) 6 of 8. The lesions in the two negative cases in the latter series were confined to the retrobulbar part of the nerve as were the two negative ones in our series. Takahashi et al. (1973) stated that in the secondary group 90% had bone changes. We found abnormality in 13 of the 14 cases and agree also with Lloyd (1971) that diffuse hyperostosis affecting the greater and lesser wings of the sphenoid is the most common abnormality. Arteriography. Susac et al. (1977) noted that two out of two were normal despite using subtraction.

MENINGIOMA

109

Lloyd (1971) reported that four of seven were negative despite subtraction and only one had shown pathological circulation. He felt that this was the only one in which significant diagnostic information had been obtained. However, Takahashi et al. (1973) noted displacement and pathological circulation in five out of six. In our series, abnormality was seen in two of the three cases in the primary group, one of which had tumour blush. Abnormality was present in 10 of the 13 which had subtraction angiography in the secondary group, a tumour blush being present in five, No relevant literature can be found to compare with this group. Venography. There does not appear to be any . relevant literature relating to the orbital venogram and cavernous sinus findings in primary and secondary orbital meningioma. In our primary group, abnormalities were present in the three cases. In the secondary group, venography showed abnormality in 9 of the 11 cases examined. Susac et al. (1977) described the difficulties they had experienced in detecting small meningiomas in the extreme posterior portion of the orbit just anterior to the optic forarnen. They did not, however, use venography which has a special place for investigating lesions in this region. Basal views to demonstrate the cavernous sinus are now done routinely as part of an orbital venograrn investigation because important information has been obtained. In one primary case it was shown that the lesion had extended through into the anterior half of the cavernous sinus and in the secondary group, five of 10 had displacement and/or non-filling. Scintiscan. Henderson (1973) stated that isotope examination was not of much value in demonstrating orbital lesions because the cavernous sinuses and mucosal linings are disproportionately vascular with the result that tracer substances tend to become concentrated there and obscure the orbital appearances. In the present investigation, scintiscan examination was negative in the only primary case so examined but was positive in all seven secondary cases examined. It is, therefore, clearly helpful in showing that a lesion is present but does not demonstrate so clearly as the other methods of investigation the situation of the turnout and cannot show actual intra-orbital extension. EM1. Wright et al. (1975) reported that CT scanning demonstrated 93% of orbital space occupying lesions. They concluded that CT was not infallible and should complement other existing non-invasive procedures. Wackenheim et al. (1977) reported that by density estimation one could not differentiate between orbital tumours. They thought, however, that meningiornas showed the highest attenuation increase after contrast of any orbital lesion. Wende et al_ (1977)

ll0

CLINICAL RADIOLOGY

considered that it was impossible to differentiate a benign from a malignant lesion b y density estimation. Glydensted et al. (1977) reported that the density range for three primary and seven secondary orbital meningiomas was 5 - 3 8 EMI units, with a mean of 18. The range of increase after contrast was 6 - 2 3 with a mean of 14. In the present series the densities in the pre-enhancement state were rather greater b u t the increase after enhancement rather less. These findings suggest that density estimations are not of value in suggesting a diagnosis of meningioma (being not dissimilar from densities seen in other conditions)• Plain film examination was in fact that which most often suggested the diagnosis• The EMI scan was negative in two of our cases and did n o t show extension from the orbit into the cavernous sinus in one, abnormalities that were detected b y venography. A combination, therefore, of plain and contrast radiology with computed tomography is likely to increase the diagnostic accuracy and the full extent of a lesion may not be appreciated if only one investigation is performed. Further, the clinical presentation of the patients in this series show that intracranial investigation is required also where an orbital space occupying lesion is suspected and that orbital examination should be done when an intracranial peri-orbital meningioma is diagnosed. REFERENCES

Craig, C. M. & Gogella, L. L. (1949). Intraorbital meningiomas. American Journal of Ophthalmology, 32, 1663 1680.

Cushing, H. & Eisenhardt, L_ (1938). In Mening~omas. Charles C. Thomas, Illinois. Glydensted, C., Lester, J. & Fledelius, H. (1977)• Computed tomography of orbital lesions. A radiological study of 141 cases. Neuroroadiology, 13, 141-150. Henderson, J. W. (1973). In Orbital Turnouts. W. B. Saunders Company, Philadelphia, London, Toronto. Karp, L. A., Zimmerman, L. E., Borit, A. & Spencer, ~/, (1974), Primary intraorbital meningiomas. Archives of Ophthalmology, 91, 24-28• Lloyd, G. A. S. (1971). The radiology of primary orbital meningioma. British Journal of Radiology, 44,405-411. Leber (1877). Cited by Byers, W. G. M. (1901). The primary intradural tumours of the optic nerve: Fibromatosis nervi optici. Stud. Royal Victoria Hospital, Montral, 1, 1-82. Lombardi, G. (1967). In Radiology in Neuro-oph thalrnology, Williamsand Wilkins,Baltimore. Susac, J. O., Smith, J. L. & Walsh, F. B. (1977). The irn, possible meningioma. Archives of Neurology, 34, 36-38. Takahashi, M., Lombardi, G., Passerini, A. & Obno, S. (1973). Primary intraorbital meningiomas: roentgenologi¢ • study. Neuroradiology, 5, 95-101. Wackenheim, A., van Damme, W., Kosmann, P. & Bittighoffer. B. (1977). Computed tomography i n ophthalmology. Denisty changes with orbital lesions. Neuroradiology, 13, 135-138. Walsh, F. B. (1970). Meningiomas, primary, within the orbit and optic canals. In Neuro-ophthalrnology Symposium of the University of Miami and the Bascorn Palmer Eye Institute, ed. Smith, J. L., Vol. 5, pp. 240-266. C. V. Mosby Co., St Louis. Wende, S., Aulich, A., Nover, A., Lanksch, W., Kazner, E., Steinhoff, H., Meese, W., Lange, S. & Grumme, T_ (1977). Computed tomography of orbital lesions. A cooperative study of 210 cases. Neuroradiology, 13, 123-134. Wright, J. E., Lloyd, G_ A. S. & Ambrose, J. (1975). Computerised axial tomography in the detection of orbital space occupying lesions. American Journal of Ophthalmology, 80, 78-84.

The radiology or orbital meningioma.

Clin.Radiol. (1979) 30, 105-110 The Radiology of Orbital Meningioma pETER MACPHERSON From the Department o f Neuroradiology, Institute o f Neurologic...
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