Clinical Radiology (1992) 45, 23-26
Intracranial Extension of Orbital Pseudotumour A. G. CLIFTON, R. L. BORGSTEIN*, I. F. MOSELEY*~, B. E. K E N D A L L ? and P. J. SHAW
University College Hospital, *Moorfields Eye Hospital, and +The National Hospital for Neurology and Neurosurgery, London Radiologically demonstrable intracranial extension of orbital pseudotumour is rare, and only four cases appear to have been reported previously in the literature. A review of the computed tomographic (CT) images of 90 biopsy proven cases of orbital pseudotumour seen over a I0 year period revealed eight cases with intracranial meningeal spread. Clifton, A.G., Borgstein, R.L., Moseley, I.F., Kendall, B.E. & Shaw, P.J. (1992). Clinical Radiology 45, 23 26. Intracranial Extension of Orbital Pseudotumour
The term 'orbital pseudotumour' (synonym: 'orbital granuloma') is used to describe an idiopathic inflammatory process arising within the orbit, which usually produces pain, proptosis and limitation of eye movement; vision may also be affected. The lesion mimics turnouts or infections, but no neoplastic cells or infective agent are found on biopsy or subsequent clinical follow up; and there is no evidence of a collagen disease or other systemic illness (Blodi and Gass, 1968). Sometimes the chronic inflammatory process extends beyond the orbit, but direct spread along the intracranial meninges, as described here in several cases, is relatively uncommon.
PATIENTS AND M E T H O D S The computed tomographic (CT) studies were reviewed of all patients with clinically diagnosed orbital pseudotumour in whom biopsy confirmed the presence of non-specific inflammatory tissue and/or fibrosis at Moorfields Eye Hospital, The National Hospital for Neurology and Neurosurgery, and University College Hospital since 1980. The review was directed at seeking evidence of intracranial extension, the following patterns being identified: (i) abnormal (i.e. contrast-enhancing) soft tissue extending through and obliterating the normal fatty plane at the superior orbital fissure into the middle cranial fossa; (ii) expansion of the ipsilateral cavernous sinus; and (iii) abnormal thickening.and/or enhancement of the meninges more distantly, in continuity with the orbital lesion. CT studies were available in 90 cases. In 82 of these (91.2%) the lesion appeared to be confined to the orbit. In eight patients (8.8%) there was CT evidence of intracranial extension, consisting in six of localized posterior extension, i.e. patterns (i) and (ii), but in two patients the intracranial involvement was more extensive, i.e. pattern (iii), and one of these had bilateral orbital disease. No extension of the disease into the anterior cranial fossa was found. Correspondence to: Dr A. G. Clifton, Department of Radiology, Atkinson Morley's Hospital, Copse Hill, Wimbledon, London SW20 ONE.
The CT findings and clinical features in these eight patients are given in Tables 1 and 2 respectively.
DISCUSSION Orbital pseudotumour was first described by Bfisse and Hochheim (1903), although credit is usually accorded to Birch-Hirschfeld (1905) who coined the descriptive term. The histological findings vary, although recently it has been emphasized that they enable a positive diagnosis to be made, and not simply a diagnosis by exclusion (Blodi and Gass, 1968). Orbital pseudotumour is one of the commoner diseases seen in eye clinics, and has been estimated to represent almost 10% of orbital masses (Henderson, 1973). A recent review of the CT characteristics of orbital pseudotumours revealed (Flanders et al., 1989): Infiltration of the retrobulbar fat 76"/0 Enlargement of the extraocular muscles - 57°/,, Thickening of the optic nerve/sheath complex 38% Contrast enhancement - 95% Proptosis 71%. Spread into the adjacent paranasal sinuses, although rare, is well documented (Eschagian and Anderson, 1981 ; Edwards et al., 1982). A few cases have been described of biopsy-proven pseudotumours arising within the orbit and extending intracranially, through the superior orbital fissure, along the meninges. Jackson (1958) operated on a 25-year-old woman with progressive visual loss, and found a mass behind the eyeball which extended through the superior orbital fissure and infiltrated the meninges of the middle cranial fossa; biopsy revealed orbital pseudotumour. In another patient, documented with CT by Kaye et al, (1984), progression of the tumour was documented over a 2 year period from a mass confined to the orbit to one extending upwards from the planum sphenoidale into the anterior cranial fossa. Noble et al. (1986) reported a primary orbital lesion spreading to the meninges of the anterior and middle cranial fossae and involving the surface of the frontal lobe. Granulomata may occur within the orbit (orbital pseudotumour), within the orbital fissure or within the
24
CLINICAL RADIOLOGY
Fig. 1 Case 4, axial enhanced CT. Right orbital mass is shown which thickens the lateral rectus bundle and extends through the superior orbital fissure in to the middle cranial fossa (arrow),
(b)
(a) Fig. 2 Case 5, axial enhanced CT. Slices at three levels reveal abnormal soft tissue in both orbits, extending intracranially to involve both cavernous sinuses and the tentoriurn and to thicken the falx and convcxity dura of the right hemisphere (arrow).
(c)
INTRACRANIAL EXTENSION OF ORBITAL PSEUDOTUMOUR
25
Fig. 3 Case 6, axial enhanced CT. An extensive right orbital mass is present which extends into the right cavernous sinus.
(/,)
(a) Fig. 4 Case 7, axial enhanced CT. (a) Orbits. (b), (c) intracranial sections. Abnormal soft tissue is present at the apex of the left orbit, which extends into the anterior part of the cavernous sinus. The higher sections show thickening and abnormal enhancement of the tentorium and posterior part of the falx. There is low attenuation of the occipital lobes suggesting oedema, which spreads into the left temporal lobe.
(c)
26
CLINICAL RADIOLOGY
Table 1 - Orbital pseudotumour invading intracranial compartments. C T characteristics
Patient no.
Through superior orbital fissure into middle fossa
Extension into the ipsilateral cavernous sinus
Abnormal thickening and/or enhancement of meninges
1
+
+
--
2
3 4
+ + +
. + --
5 6 7 8
+ + + +
+ + + +
.
.
Bilateral orbital involvement
Figure
--
--
.
-
--
1
+ -+ --
+ ----
2a, b and c 3 4a, b and c --
Table 2 - Orbital pseudotumour invading intracranial compartments. Clinical features in eight patients
Patient no.
Sex
Age
Duration o f symptoms beJore CT
Cranial nerve palsies
R 3, 4 and 6 R 3, 4 and 6 L6
1 2 3 4 5 6 7
M M F M M F M
49 69 54 36 86 71 30
1 year 7 months 3 years 1 month 18 months 6 years i month
8
M
61
1 year
R 3, 4 and 6 L3, 4, 6 and 5
c a v e r n o u s sinus ( T o l o s a - H u n t s y n d r o m e ) . P r e s e n t a t i o n t h e n d e p e n d s u p o n the precise a n a t o m i c a l l o c a l i z a t i o n a n d the d e g r e e o f a c t i v i t y o f the g r a n u l o m a t o u s r e s p o n s e . B i o p s y is necessary in o r d e r to e x c l u d e i n f l a m m a t o r y o r n e o p l a s t i c i n f i l t r a t i o n s ( S a n d e r s a n d M o s e l e y , 1979). A s w i t h lesions c o n f i n e d to the orbits, a c c u r a t e p r e - o p e r a t i v e d i a g n o s i s is o f t e n i m p o s s i b l e . M a g n e t i c r e s o n a n c e i m a g ing o f t e n d e l i n e a t e s the a b n o r m a l i t y m o r e a c c u r a t e l y ( Y o u s e m e t al., 1990; G o t o e t al., 1990). T h e e t i o l o g y o f o r b i t a l p s e u d o t u m o u r is u n k n o w n . L e v y e t al. (1975) r e c o r d e d p a t i e n t s in w h o m o r b i t a l o r retroorbital pseudotumours were associated with mediastinal o r r e t r o p e r i t o n e a l fibrosis, R i e d e l ' s t h y r o i d i t i s , Dupuytren's contracture or sclerosing cholangitis. Goto e t al. (1989), f r o m a s t u d y o f 12 p a t i e n t s w i t h i d i o p a t h i c p a i n f u l o p h t h a l m o p l e g i a , f o u n d an o c c l u d e d s u p e r i o r o p h t h a l m i c v e i n w h i c h m a n i f e s t e d as a C T a b n o r m a l i t y . T h e y suggest t h a t t h e C T a b n o r m a l i t y m a y reflect a c h r o n i c i n f l a m m a t o r y p r o c e s s o r else, o e d e m a r e s u l t i n g f r o m o c c l u s i o n o f the s u p e r i o r o p h t h a l m i c vein o r c a v e r n o u s sinus. S o m e p a t i e n t s w i t h o r b i t a l p s e u d o t u m o u r receive t r e a t m e n t w i t h s y s t e m i c c o r t i c o s t e r o i d s o n the basis o f clinical assessment and CT alone, biopsy being considered unnecessary. T h e i m p o r t a n c e o f b i o p s y in d i a g n o s i s was e m p h a s i z e d by the e x p e r i e n c e w i t h t w o p a t i e n t s e n c o u n t e r e d in this study, in w h o m the initial p r e s u m p t i v e diagnosis of orbital pseudotumour, made on CT and clinical g r o u n d s , s u b s e q u e n t l y p r o v e d to be i n c o r r e c t . In b o t h p a t i e n t s the c o r r e c t d i a g n o s i s o f l y m p h o m a was m a d e by b i o p s y a f t e r p o o r r e s p o n s e to t r e a t m e n t w i t h a d e l a y o f 3 years in the o n e p a t i e n t . I n o u r series o f 90 cases, 8 . 8 % o f o r b i t a l p s e u d o t u m o u r s w e r e f o u n d to s h o w C T e v i d e n c e o f i n t r a c r a n i a l extension-a p e r c e n t a g e h i g h e r t h a n p r e v i o u s l y described. Acknowledgements. We would like to thank Professor R. L. Souhami of University College Hospital for his help in the preparation of this paper.
Popilloedema
Presenting symptoms
Response to steroids"
Pain
Proptosis
Vision
+ Bilateral +
+ + + + + +
+ + + + + +
+ + + + + + +
Pale discs
+
+
+
Good
Poor Initially good, then deteriorated Poor
REFERENCES
Birch-Hirschfeld, A (191)5). Zur Diagnostik und Pathologie der Orbitaltumoren. Bericht iiber die Zweiunddreissigste VeJ~famrnlung der Ophthahnologischen GesellschaJL 32, 127 135. Blodi, FC & Gass, JDM 11968). Inflammatory pseudotumour of the orbit. British Journal g f Ophthalmology, 52, 79-93. B/isse, O & Hochheim, W (1903). Uber syphilitische Entz/indung der ausseren (Augenmuskeln und des Herzens. Albrecht yon Grae/i,s Archiv fiir Ophthahnologie vereinLgt mit Archiv .fiir Augenheilkunde (Munchen), 55, 222 238.
Edwards, MK, Zauel, DW, Gilmor, RL & Muller, J (1982). lnvasive orbital pseudotumour-CT demonstration of.extension beyond orbit. Neuroradiology, 23, 215 217. Eschagian, J & Anderson, RL (1981). Sinus involvement in inflammatory orbital pseudotumour. Arehives o f Ophthalmology, 99, 627 630. Flanders, AE, Mafee, MF, Rao, VM & Choi, KH (1989). CT characteristics of orbital pseudotumors and other orbital inflammatory processes. Journal o1" Computer Assis'ted Tomography, 13, 40--47. Goto, Y, Goto, l & Hosokawa, S (1989). Neurological and radiological studies in painful ophthalmoplegia: Tolosa-Hunt syndrome and orbital pseudotumour. Journal of Neurology, 236, 448--451. Goto, Y, Hosokawa, S, Goto, I, Hirakata, R & Hasuo, K 11990). Abnormality in the cavernous sinus in three patients with TolosaHunt syndrome: MRI and CT findings. Journal o f Neurology, Neurosurgery and Psychiatry, 53, 231 234. Henderson, JW (1973). Orbital Tumors, pp. 555-588. WB Saunders, Philadelphia. Jackson, H (1958). Pseudotumour of the orbit. British Journal of Ophthalmology, 42, 212 224. Kaye, AH, Hahn, JH, Cracium, A, Hanson, M, Berlin, AJ & Tubbs, RT (1984). Intracranial extension of inflammatory pseudotumor of the orbit. Journal of Neurosurgery, 60, 625 629. Levy, IS, Wright, JE & Lloyd, GAS (1975). Orbital and retro-orbital pseudotumour. Modern Problems in Ophthalmology, 14, 364 367. Noble, SC, Chandler, WF & Lloyd, RV (1986). Intracranial extension of orbital pseudotumor: a case report. Neurosurgery, 18, 798 801. Sanders, MD & Moseley, IF (1979). CT scanning in neuroophthalmology: optic nerve compression. In Topics in Neuroophthalmology, ed. Thomson, HS, p. 334. Williams and Wilkins, Baltimore. Yousem, DM, Atlas, SW, Grossman, RI, Sergott, RC, Savino, PJ & Bosley, TM (1990). MR imaging of Tolosa-Hunt syndrome. American Journal o f Roentgenology, 154, 167 170.
Intracranial Extension of Orbital Pseudotumour A. G. CLIFTON, R. L. BORGSTEIN*, I. F. MOSELEY*~, B. E. K E N D A L L ? and P. J. SHAW
University College Hospital, *Moorfields Eye Hospital, and +The National Hospital for Neurology and Neurosurgery, London Radiologically demonstrable intracranial extension of orbital pseudotumour is rare, and only four cases appear to have been reported previously in the literature. A review of the computed tomographic (CT) images of 90 biopsy proven cases of orbital pseudotumour seen over a I0 year period revealed eight cases with intracranial meningeal spread. Clifton, A.G., Borgstein, R.L., Moseley, I.F., Kendall, B.E. & Shaw, P.J. (1992). Clinical Radiology 45, 23 26. Intracranial Extension of Orbital Pseudotumour
The term 'orbital pseudotumour' (synonym: 'orbital granuloma') is used to describe an idiopathic inflammatory process arising within the orbit, which usually produces pain, proptosis and limitation of eye movement; vision may also be affected. The lesion mimics turnouts or infections, but no neoplastic cells or infective agent are found on biopsy or subsequent clinical follow up; and there is no evidence of a collagen disease or other systemic illness (Blodi and Gass, 1968). Sometimes the chronic inflammatory process extends beyond the orbit, but direct spread along the intracranial meninges, as described here in several cases, is relatively uncommon.
PATIENTS AND M E T H O D S The computed tomographic (CT) studies were reviewed of all patients with clinically diagnosed orbital pseudotumour in whom biopsy confirmed the presence of non-specific inflammatory tissue and/or fibrosis at Moorfields Eye Hospital, The National Hospital for Neurology and Neurosurgery, and University College Hospital since 1980. The review was directed at seeking evidence of intracranial extension, the following patterns being identified: (i) abnormal (i.e. contrast-enhancing) soft tissue extending through and obliterating the normal fatty plane at the superior orbital fissure into the middle cranial fossa; (ii) expansion of the ipsilateral cavernous sinus; and (iii) abnormal thickening.and/or enhancement of the meninges more distantly, in continuity with the orbital lesion. CT studies were available in 90 cases. In 82 of these (91.2%) the lesion appeared to be confined to the orbit. In eight patients (8.8%) there was CT evidence of intracranial extension, consisting in six of localized posterior extension, i.e. patterns (i) and (ii), but in two patients the intracranial involvement was more extensive, i.e. pattern (iii), and one of these had bilateral orbital disease. No extension of the disease into the anterior cranial fossa was found. Correspondence to: Dr A. G. Clifton, Department of Radiology, Atkinson Morley's Hospital, Copse Hill, Wimbledon, London SW20 ONE.
The CT findings and clinical features in these eight patients are given in Tables 1 and 2 respectively.
DISCUSSION Orbital pseudotumour was first described by Bfisse and Hochheim (1903), although credit is usually accorded to Birch-Hirschfeld (1905) who coined the descriptive term. The histological findings vary, although recently it has been emphasized that they enable a positive diagnosis to be made, and not simply a diagnosis by exclusion (Blodi and Gass, 1968). Orbital pseudotumour is one of the commoner diseases seen in eye clinics, and has been estimated to represent almost 10% of orbital masses (Henderson, 1973). A recent review of the CT characteristics of orbital pseudotumours revealed (Flanders et al., 1989): Infiltration of the retrobulbar fat 76"/0 Enlargement of the extraocular muscles - 57°/,, Thickening of the optic nerve/sheath complex 38% Contrast enhancement - 95% Proptosis 71%. Spread into the adjacent paranasal sinuses, although rare, is well documented (Eschagian and Anderson, 1981 ; Edwards et al., 1982). A few cases have been described of biopsy-proven pseudotumours arising within the orbit and extending intracranially, through the superior orbital fissure, along the meninges. Jackson (1958) operated on a 25-year-old woman with progressive visual loss, and found a mass behind the eyeball which extended through the superior orbital fissure and infiltrated the meninges of the middle cranial fossa; biopsy revealed orbital pseudotumour. In another patient, documented with CT by Kaye et al, (1984), progression of the tumour was documented over a 2 year period from a mass confined to the orbit to one extending upwards from the planum sphenoidale into the anterior cranial fossa. Noble et al. (1986) reported a primary orbital lesion spreading to the meninges of the anterior and middle cranial fossae and involving the surface of the frontal lobe. Granulomata may occur within the orbit (orbital pseudotumour), within the orbital fissure or within the
24
CLINICAL RADIOLOGY
Fig. 1 Case 4, axial enhanced CT. Right orbital mass is shown which thickens the lateral rectus bundle and extends through the superior orbital fissure in to the middle cranial fossa (arrow),
(b)
(a) Fig. 2 Case 5, axial enhanced CT. Slices at three levels reveal abnormal soft tissue in both orbits, extending intracranially to involve both cavernous sinuses and the tentoriurn and to thicken the falx and convcxity dura of the right hemisphere (arrow).
(c)
INTRACRANIAL EXTENSION OF ORBITAL PSEUDOTUMOUR
25
Fig. 3 Case 6, axial enhanced CT. An extensive right orbital mass is present which extends into the right cavernous sinus.
(/,)
(a) Fig. 4 Case 7, axial enhanced CT. (a) Orbits. (b), (c) intracranial sections. Abnormal soft tissue is present at the apex of the left orbit, which extends into the anterior part of the cavernous sinus. The higher sections show thickening and abnormal enhancement of the tentorium and posterior part of the falx. There is low attenuation of the occipital lobes suggesting oedema, which spreads into the left temporal lobe.
(c)
26
CLINICAL RADIOLOGY
Table 1 - Orbital pseudotumour invading intracranial compartments. C T characteristics
Patient no.
Through superior orbital fissure into middle fossa
Extension into the ipsilateral cavernous sinus
Abnormal thickening and/or enhancement of meninges
1
+
+
--
2
3 4
+ + +
. + --
5 6 7 8
+ + + +
+ + + +
.
.
Bilateral orbital involvement
Figure
--
--
.
-
--
1
+ -+ --
+ ----
2a, b and c 3 4a, b and c --
Table 2 - Orbital pseudotumour invading intracranial compartments. Clinical features in eight patients
Patient no.
Sex
Age
Duration o f symptoms beJore CT
Cranial nerve palsies
R 3, 4 and 6 R 3, 4 and 6 L6
1 2 3 4 5 6 7
M M F M M F M
49 69 54 36 86 71 30
1 year 7 months 3 years 1 month 18 months 6 years i month
8
M
61
1 year
R 3, 4 and 6 L3, 4, 6 and 5
c a v e r n o u s sinus ( T o l o s a - H u n t s y n d r o m e ) . P r e s e n t a t i o n t h e n d e p e n d s u p o n the precise a n a t o m i c a l l o c a l i z a t i o n a n d the d e g r e e o f a c t i v i t y o f the g r a n u l o m a t o u s r e s p o n s e . B i o p s y is necessary in o r d e r to e x c l u d e i n f l a m m a t o r y o r n e o p l a s t i c i n f i l t r a t i o n s ( S a n d e r s a n d M o s e l e y , 1979). A s w i t h lesions c o n f i n e d to the orbits, a c c u r a t e p r e - o p e r a t i v e d i a g n o s i s is o f t e n i m p o s s i b l e . M a g n e t i c r e s o n a n c e i m a g ing o f t e n d e l i n e a t e s the a b n o r m a l i t y m o r e a c c u r a t e l y ( Y o u s e m e t al., 1990; G o t o e t al., 1990). T h e e t i o l o g y o f o r b i t a l p s e u d o t u m o u r is u n k n o w n . L e v y e t al. (1975) r e c o r d e d p a t i e n t s in w h o m o r b i t a l o r retroorbital pseudotumours were associated with mediastinal o r r e t r o p e r i t o n e a l fibrosis, R i e d e l ' s t h y r o i d i t i s , Dupuytren's contracture or sclerosing cholangitis. Goto e t al. (1989), f r o m a s t u d y o f 12 p a t i e n t s w i t h i d i o p a t h i c p a i n f u l o p h t h a l m o p l e g i a , f o u n d an o c c l u d e d s u p e r i o r o p h t h a l m i c v e i n w h i c h m a n i f e s t e d as a C T a b n o r m a l i t y . T h e y suggest t h a t t h e C T a b n o r m a l i t y m a y reflect a c h r o n i c i n f l a m m a t o r y p r o c e s s o r else, o e d e m a r e s u l t i n g f r o m o c c l u s i o n o f the s u p e r i o r o p h t h a l m i c vein o r c a v e r n o u s sinus. S o m e p a t i e n t s w i t h o r b i t a l p s e u d o t u m o u r receive t r e a t m e n t w i t h s y s t e m i c c o r t i c o s t e r o i d s o n the basis o f clinical assessment and CT alone, biopsy being considered unnecessary. T h e i m p o r t a n c e o f b i o p s y in d i a g n o s i s was e m p h a s i z e d by the e x p e r i e n c e w i t h t w o p a t i e n t s e n c o u n t e r e d in this study, in w h o m the initial p r e s u m p t i v e diagnosis of orbital pseudotumour, made on CT and clinical g r o u n d s , s u b s e q u e n t l y p r o v e d to be i n c o r r e c t . In b o t h p a t i e n t s the c o r r e c t d i a g n o s i s o f l y m p h o m a was m a d e by b i o p s y a f t e r p o o r r e s p o n s e to t r e a t m e n t w i t h a d e l a y o f 3 years in the o n e p a t i e n t . I n o u r series o f 90 cases, 8 . 8 % o f o r b i t a l p s e u d o t u m o u r s w e r e f o u n d to s h o w C T e v i d e n c e o f i n t r a c r a n i a l extension-a p e r c e n t a g e h i g h e r t h a n p r e v i o u s l y described. Acknowledgements. We would like to thank Professor R. L. Souhami of University College Hospital for his help in the preparation of this paper.
Popilloedema
Presenting symptoms
Response to steroids"
Pain
Proptosis
Vision
+ Bilateral +
+ + + + + +
+ + + + + +
+ + + + + + +
Pale discs
+
+
+
Good
Poor Initially good, then deteriorated Poor
REFERENCES
Birch-Hirschfeld, A (191)5). Zur Diagnostik und Pathologie der Orbitaltumoren. Bericht iiber die Zweiunddreissigste VeJ~famrnlung der Ophthahnologischen GesellschaJL 32, 127 135. Blodi, FC & Gass, JDM 11968). Inflammatory pseudotumour of the orbit. British Journal g f Ophthalmology, 52, 79-93. B/isse, O & Hochheim, W (1903). Uber syphilitische Entz/indung der ausseren (Augenmuskeln und des Herzens. Albrecht yon Grae/i,s Archiv fiir Ophthahnologie vereinLgt mit Archiv .fiir Augenheilkunde (Munchen), 55, 222 238.
Edwards, MK, Zauel, DW, Gilmor, RL & Muller, J (1982). lnvasive orbital pseudotumour-CT demonstration of.extension beyond orbit. Neuroradiology, 23, 215 217. Eschagian, J & Anderson, RL (1981). Sinus involvement in inflammatory orbital pseudotumour. Arehives o f Ophthalmology, 99, 627 630. Flanders, AE, Mafee, MF, Rao, VM & Choi, KH (1989). CT characteristics of orbital pseudotumors and other orbital inflammatory processes. Journal o1" Computer Assis'ted Tomography, 13, 40--47. Goto, Y, Goto, l & Hosokawa, S (1989). Neurological and radiological studies in painful ophthalmoplegia: Tolosa-Hunt syndrome and orbital pseudotumour. Journal of Neurology, 236, 448--451. Goto, Y, Hosokawa, S, Goto, I, Hirakata, R & Hasuo, K 11990). Abnormality in the cavernous sinus in three patients with TolosaHunt syndrome: MRI and CT findings. Journal o f Neurology, Neurosurgery and Psychiatry, 53, 231 234. Henderson, JW (1973). Orbital Tumors, pp. 555-588. WB Saunders, Philadelphia. Jackson, H (1958). Pseudotumour of the orbit. British Journal of Ophthalmology, 42, 212 224. Kaye, AH, Hahn, JH, Cracium, A, Hanson, M, Berlin, AJ & Tubbs, RT (1984). Intracranial extension of inflammatory pseudotumor of the orbit. Journal of Neurosurgery, 60, 625 629. Levy, IS, Wright, JE & Lloyd, GAS (1975). Orbital and retro-orbital pseudotumour. Modern Problems in Ophthalmology, 14, 364 367. Noble, SC, Chandler, WF & Lloyd, RV (1986). Intracranial extension of orbital pseudotumor: a case report. Neurosurgery, 18, 798 801. Sanders, MD & Moseley, IF (1979). CT scanning in neuroophthalmology: optic nerve compression. In Topics in Neuroophthalmology, ed. Thomson, HS, p. 334. Williams and Wilkins, Baltimore. Yousem, DM, Atlas, SW, Grossman, RI, Sergott, RC, Savino, PJ & Bosley, TM (1990). MR imaging of Tolosa-Hunt syndrome. American Journal o f Roentgenology, 154, 167 170.
