Compurerrzrd

Tomoqroph!,

0

Press Ltd

Pergamon

Vol. 3. PP. 241 10 265 1979. Printed

in Great

ORBITAL

0363.8235

79 1201-0241502.00’0

Britam

SYNDROMES-CT

ANALYSIS

OF 100 CASES

F. GUIBERT-TRANIER, J. PITON, A. CALABET and J. M. CAILLB Service Neuroradiologie,

Hhpital Pellegrin-Tripode, Place Amelie-Raba-Leon, 33076 Bordeaux Cedex, France

(Received 10 July 1979; received

for puhliccrtion

10 September

1979)

Abstract-100 cases of orbital syndromes,primary or secondary,

are reviewed after CT analysis and compared with the results of plain and angiographic conventional examinations. First, the technique and normal results are described. Primary orbital syndromes (45 cases) originating in the orbit form three subgroups-tumors of the eyeball, tumors limited to the orbit and tumors of the orbit with bone lesions, with or without extra-orbital extension. Secondary orbital syndromes (55 cases) spreading to the orbit contain malignant tumors (36 cases) of which 25 are epitheliomas and benign tumors, the most frequent being meningiomas. For ocular and orbital tumors, CT allows the diagnosis of a mass and sometimes the pathological diagnosis (endocrine exophtalmos, inflammatory pseudotumors, varicose ophthalmic veins). For all other orbital tumors CT is important in determining the volume, relationships and extension, and does so better than carotid angiography or orbital phlebography. In secondary orbital syndromes, and particularly in facial malignant tumors and in meningiomas, CT is of great interest in the pretherapeutic evaluation of a tumor. It shows its volume and extension toward the face and orbital cavities, the pterygo-maxillary fossa (so important in determining the operability), the infra-temporal fossa and the endocranium, often without resorting to complementary investigational procedures which are much more aggressive. After histological diagnosis, CT allows the establishment of a therapeutic program.

Orbital

syndromes

Pretherapeutic

CT evaluation

INTRODUCTION

Progress in CT scanning techniques during the last few years has led to such precision that CT can be used in studying structures which are very small and often invisible to conventional radiology. The increase in spatial resolution, the decrease in calculation and acquisition times, and the possibility of reconstruction in sagittal and frontal planes allow a fine and detailed anatomical study of the orbit and its nervous and musculo-aponeurotic contents. Exploration of facial structures and the search for endocranial extension may be performed simultaneously. Thus, compared to conventional neuroradiology, CT has led to considerable progress in that it allows simultaneous exploration of bony structures and soft tissues without resorting to complementary investigational procedures which are frequently aggressive. Using CT, we have analyzed the entirety of orbital pathology, including peripheral neurological problems (decreased visual acuity, loss of extrinsic motor function) and inflammatory, infectious, traumatic, or neoplastic pathology. Studying 100 cases, we have tried to establish diagnostic correlations using CT data. MATERIALS

AND

METHODS

Exumination Technique The examinations were carried out using a ND 8000 (C.G.R.) with the following specifications: 512 x 512 calculation matrix; 256 x 256 exposition matrix with optional calculated zoom (pixel size, 0.5 x 0.5 mm); acquisition time: 80 set for a 360” rotation, 40 set for 180”; three available filters, the most frequently used made of 2 mm thick aluminium. Slice thickness can be 3, 6 or 9 mm. In exploring facial structures and the orbit, contiguous 6 mm sections are made, sometimes 3 mm sections or overlapping sections (6 mm sections made every 3 mm). The rotation is 360” with spatial resolution. Two incidences, axial and coronal, are systematically performed [26]. Tridimensional reconstruction makes sagittal sections possible: (a) axial incidence; the ideal plane for exploration of the orbits is parallel to its floor, and passes by the line joining the infra-orbital margin and the superior point * Service

Neuroradiologie,

HBpital

Pellegrin-Tripode,

Bordeaux, 241

France.

F. GUIBERT-TRANIER, J. PITON, A. CALABETand J. M. CAILLB

242

of insertion of the ear on the scalp [32] and (b) coronal incidence; the patient’s head is extended, the gantry inclined at an angle of - 20 to - 30”. When the patient cannot maintain this position, he is seated in front of the gantry, head inserted in the tunnel, gantry inclined from + 20 to + 30”. In the coronal incidence, interpretation is sometimes impossible due to metallic dental artifacts. In such cases, the gantry is inclined so that the beam misses the metal. The injection of contrast medium is not systematically performed. Case Analyses

The following elements were analyzed in each of the 100 cases: (a) The orbit and its contents (bone structure, extrinsic musculature, optic nerve, eyeball and vessels, (b) The facial structures and sinuses, (c) The base of the skull and (d) The endocranium. CT data is compared, as much as possible, with the results of plain and angiographic conventional examinations. All readings are made directly on the console using images stored in the floppy disc. Normal Images [28,31] The orbits Axial sections (Fig. 2). (i) The orbit walls; the medial and lateral walls can be studied well using this incidence. The entire length of the optic canal is visible. (ii) The eyeball; the transparent media of the eye are hypodense in CT, and are surrounded by a dense border representing the sclera and the choroid which cannot be differentiated from each other. The lens is biconvex, dense, and easily visualized in the anterior part of the eyeball. (iii) The optic nerve is not always seen entirely in one given section. It passes through the center of the orbit and follows a straight or bayonet path. The nerve is mobilized by ocular movements. (iv) The musculo-aponeurotic cone; the fatty structures of the orbit outline very precisely the elements of the cone: in the axial incidence, the medial and lateral recti are perfectly seen. In higher sections, it is usually impossible to distinguish the ophthalmic vein of the superior muscles of the eye (superior rectus, levator palpebrae and superior oblique). Coronal sections: [2] (Fig. 4). (i) The orbit walls: this incidence in particular’ enables us to study the superior and inferior walls which are poorly analyzed in the axial incidence. In the posterior sections, the superior orbital fissure and the elements which penetrate it are easily seen. (ii) The.eyeball; studied in the 2 or 3 anterior sections, the four rectus muscles are distinguishable. (iii) A cross-section of the optic nerve is seen, and it is interesting to study its caliber using this incidence. (iv) The musculo-aponeurotic cone; the rectus muscles and the superior oblique stand out against the hypodense fatty tissue of the orbit. The injection ofcontrast medium. We used a 38% iodine contrast medium at a dosage of 2 ml/kg of weight. The injection is an intravenous bolus. In studying the facial structures and the orbit, we have used muscle density as a reference basis before and after injection of contrast medium. All abnormal images are thus analysed according to its hypo-, iso- or hyperdensity with respect to the muscle. Injection of contrast medium is not systematic, and is only indicated when supplementary information needed for diagnosis may be obtained. In fact, tumors of the face differ from those of the brain where CT criteria, before and after injection of contrast medium, are very suggestive, if not specific, of the histological type of the tumor due to the existence of the blood-brain barrier (normally impermeable to iodine) [7, 161. The increase in density of the muscles of the face and the orbit, and of the layers of the eye (sclera and choroid layer) after injection of contrast medium is due partly to the vascularization of these structures and also to the diffusion of iodine into the extracellular space. Facial

structures

CT allows a nearly anatomical study of the facial structures: In the nasal and sinus cavities (maxillary sinuses, frontal sinuses, ethmoid cells, and sphenoid sinuses) the great difference in density between bone and air and the fineness of the bony surfaces make for the production of images almost as precise as those in conventional tomography. Normally, the mucosa which lines these structures is invisible. All pathological processes involving these cavities lead to their partial or total

Orbital

syndromes-

CT analysis

A 2.

Pterygold

3.

head

4

Petrous

243

of 100 cases

M

masseter

EI M lateral

Process

of mandible bone

Pterygotd

C

Mm longus

capitjs

D

Mm tensor

and Ievator

5.

Pltutory

fossa

E

M temporalis

6

opticus

canalis

F

M trapezlus

7

athmoid

0.

nasalcavity

9

maxillary

IO

naso-

sinus

G M medIal

Pterygoid

H

gland

Parotid

I

sirus

K

medial

rectus

M lateral

rectus

MInferior

L, M.M

superior

rectus rectus

N M Superior 0 P 0

Fig. 1. Anatomic

and tomodensitometric

axial sections through fossae.

maxillary

capitis

Palatl

globe

J M

pharynx

ond rectus

M levator optic

oblique Palpebrae

nerve

M pharyngeal

sinuses,

constrictor

cavum

and pterygoid

OnteriOr

F. GUIBERT-TRANIER, J. PITON,A. CALABET and J. M. CAILL~

244

filling. The precise analysis of these bony walls can only be obtained using axial and coronal incidences (Figs l-4). The nasopharynx lies posterior to the nasal cavity, between the pterygoid process and the tensor and levator veli palatini muscles, and anterior to the longus capitis and rectus capitis anterior muscles of the head. The cavity is absolutely median, and its walls are perfectly symmetrical. Rosenmiiller’s fossa and the mouth of the auditory tube are visible (Figs l-3). The pterygo-palatine fossa [27] is a space whose long axis is transversal, and lies posterior to the posterior wall of the maxillary sinus, anterior to the union of the two wings of the pterygoid processes, and lateral to the palatine bone. Laterally, it is continuous with the infra temporal fossa via the pterygo-maxillary foramen. It is covered by the body of the sphenoid, and inferiorly forms the pterygo-palatine canal (Fig. 1). The pterygoid fossae are bilateral, symmetrical, triangular musculo-aponeurotic spaces which lie posterior to the postero-lateral wall of the maxillary sinus. They are medial to the ramus of the mandible and the masseter muscle and lateral to the pterygoid process which is the point of insertion of the medial and lateral pterygoid muscles. These muscles form the postero-medial boundary of the pterygoid fossa. The fossa contains fatty tissue which is hypodense in CT and precisely outlines the different muscles; medial pterygoid, lateral pterygoid and masseter. Below we shall see the importance of these fatty outlines (Figs l-3). The infra-temporal fossa lies postero-lateral to the lateral wall of the orbit (zygomatic bone and greater wing of the sphenoid), antero-lateral to the temporal squama, and medial to the zygoma. This fossa contains the temporal muscle and fatty tissue. In CT, the temporal muscle is easily visualized, outlined by a hypodense fatty border. Disappearance of these outlines and filling of the infra-temporal fossa are signs of invasion. PRIMARY

ORBITAL

(ORIGINATING

We have studied 45 cases of abnormalities orbit. Three subgroups were formed:

SYNDROMES

IN THE ORBIT)

which are purely orbital or which originated in the

Tumors of the eyeball; Tumors limited to the orbit, without bone destruction and Tumors of the orbit with bone lesions with or without extra-orbital Tumors of the Eyeball-Y

extension.

Cases

Three cases of retinoblastoma in children (Fig. 5)

These tumors are restricted to the eyeball, implanted at its posterior pole, and do not alter retro-ocular soft tissue. In all three cases there exist hyperdense zones, sometimes with calcium densities which can be also found, as in one case, in the simple roentgenogram. The spontaneous density, before contrast medium, is similar to that of the lens. In two cases, the mass effect gives rise to discrete exophthalmos. The density is not modified after the injection of contrast medium. Three cases of melanoma

Again, the tumors are located in the posterior chamber of the eye. Their density is greater than that of the muscle, and approximately equal to that of the retinoblastoma. In one case, this tumor causes exophthalmos. Contrary to the opinion of certain authors [37,38], we found a relatively certain enhancement in these three patients. These three tumors appear perfectly limited to the eyeball, and no modifications of the musculo-aponeurotic cone exist. Three cases of choroid angiomas (Fig. 6)

One of these is part of a proved Sturge-Weber-Krabbe syndrome. Exophthalmos exists in two cases, and in one case it is severe. The structure of the musculo-aponeurotic cone appears normal. The tumor is, once again, well limited and shows up as a mass whose density is greater than that of muscle. In one case, there is a definite enhancement. It seems impossible, in practice, to distinguish an angioma

from a melanoma.

Orbital

syndromes-CT

analysis

of 100 cases

245

I

-1 k --D

-E

-B G A

I coronold 2 pterygold

masseter

process process

3. head of mandible 4. petrous bone

C D

5 pituitary

E M F M G M H I J M

6 7 8 9 IO.

Fig. 2. Anatomic

opticus

fossa canalis

ethmad sws nasal cowty maxillary sinus “aso- pharynx

Mm Mm

lateral

pterygoid

longus tensor

capitis and rectus and levator palqti

capltls

anterior

temporalis trapews medial pterygoid porotld gland globe medial rectum

KM L M MM NM OM P

lateral rectLl* inferior ret+“* SuperIce recta suparlor oblique levator polpebrae

PM

pharyngeal

optic nerw

and CT aspects. Left: posterior coronal sections of the facial section of the ethmoid cells and the orbits.

constrictor

structures.

Right:

axial

F.

GUIBERT-TRANIER,

J. PITON,A. CALABETand J. M. CAILL~

-E -Et

-A

I n

u

coronad

process

; !I

2. pterygoid 3 head of mandible 4. petrous bone 5. pituitary fossa 6.opticus

canalis

7. ethmoid sinus nasal cov,ty

8.

9. maxillary sinus IO. noso- pharynx

rnosseter lateral mervgold longus copitis and

c

Mm

D. E. F

Mm tensor and M M

‘GM H I J K

M Y.4

levator

medlal parotid

pterygoid gland

globe medial lateral

rectus rectus

L M MM NM 0 M

inferior rectus superior rectus superwx oblique Wator palpebrae

P

optic

a.

M

rectum

capitis

palati

temporolls tropezius

nerve

phoryngeal

constrIctor

Fig. 3. Anatomic and CT aspects. Coronal sections through the cavum and the pterygoid fossae.

OnteriOr

Orbital

I.

Coronoid

Process

2

Pterygoid

Process

3

head of mandible

syndromes-CT

analysis

247

of 100 cases

A

M

mosseter

B.

M

lateral

Pterygoid

C. Mmlongus capitis and rectus D Mmtensor and palati tempwalis E.M trapezius F. M

4

Petrous

5

Pituitary

6

opticus

canolis

GM

medial

7

ethmoid

sirus

H

Parotid

gland

8

nasalcavity

9

maxillary

LM

globe medial lateral inferior

rectus rectus rectus

z”M

superiorrBctus supenor oblique

OM P

levotor Palpebrae optic nerve

QM

pharyngeal

IO naso-

bone fosso

I sinus

Pharynx

Fig. 4. Anatomic

and CT aspects.

Coronal

sections

through

the orbits

pterygoid

ConstrlctOr

and maxillary

sinuses.

capitis

anterior

248

F. GUIBERT-TRANIER, J. PITON, A. CALABET and J. M. CAILLB

Fig. 5. Retinoblastoma.

Voluminous

calcification

of the right eyeball. (bottom).

Tumors Limited I ‘he 22 cases studied 4 CL. uses of inflammatory

were surgically pseudo-tumors

Enhancement.

Before (top) and after

to the Orbit

and histologically

verified.

(Fig. 7)

image in CT. The bony structures are not altered. In each (:ase, ‘I‘hese lesions give a characteristic of the eyeball along with homogeneous ring-shaped thickening of the SC:lera the] re is protrusion greater than muscle density. Also, there is tumefaction of the whc)se density is spontaneously cone. This aspect cal I be retr ,o-ocular soft tissue involving the entirety of the musculo-aponeurotic uni or bilateral and becomes quite characteristic after injection of contrast medium, resulting in a lesions and without t bone mai rked increase in density. This ringed image, together with retro-orbital or extension seems characteristic of this benign inflammatory pathology. One can momdifications

Orbital

Fig. 6. Choroid

angioma.

syndromes-CT

Thickening

analysis

of 100 cases

at the posterior

249

pole of the right eyeball

follow the regression of this inflammation which lasts two weeks treated with anti-inflammatory antibiotic drug therapy.

and

Six cases of orbital angiomas

Once again, the CT image is characteristic. Five times out of six, exophthalmos is present. In our observations, the relatively heterogeneous mass effect combines iso- and hyperdense images. The mass is always independent of the eyeball, and more or less completely involves the musculo-aponeurotic cone. The bony structures of the orbit are never altered in our series. The result of injection of contrast medium is variable. In two out of three cases, there is enhancement which is not as great as in the inflammatory syndromes. I

:1

F. GUIBERT-TRANIER, J. PITON, A. CALABET and J. M. CAILL~

Fig. 7. Inflammatory

pseudo-tumor.

Unilateral

tumefaction thickening.

of the retro-ocular

soft

tissue

with

scleral

Orbital

Fig. 8. Endocrine

Fig. 9. Optic

exophthalmos.

nerve meningioma.

syndromes-CT

Thickening

analysis

of the extrinsic rectus.

Axial and coronal

sections

251

of 100 cases

musculature

predominating

with and without

contrast

in the inferior

injection.

F. GUIRERT-TRANIER, J. PITON,A. CALABETand J. M. CAILL~

252

Three cases of neurofihromatosis

Here too, the CT image is representative and combines: global widening of the orbital bony structure, without osteolysis; exophthalmos without alteration of the eyeball; mass effect, which is obvious in axial and coronal sections, is iso- or hyperdense and involves primarily the musculo-aponeurotic cone in which differentiation of the extrinsic musculature becomes impossible and in one case, enhancement (obtained only two times). Three cases of endocrine

exophthalmos

(Fig. 8)

The CT image is now well known and associates a thickening of the extrinsic musculature with enhancement. Other cases fbrming a miscellaneous

group

One case of varicose ophthalmic vein including exophthalmos, a hyperdense mass effect of the cone which is opacified by contrast medium and is independent of the eyeball, and without bone modifications. A retro-ocular hematoma, obvious in context; very dense retro-ocular mass with exophthalmos. One case of orbital lymphedema; exophthalmos secondary to a mass effect of the musculo-aponeurotic cone, without enhancement, without ocular lesions, but with widening of the orbital bone structure. One basal-cell carcinoma of the medial part of the orbit; isolated hyperdense mass effect of the cone. One optic nerve meningioma; neoformation indissociable from the optic nerve and which discretely widens the orbit, with exophthalmos and opacification with contrast medium (Fig. 9). One false positive; exophthalmos with hyperdensity of the cone. Exploratory surgery reveals no anomaly. Intra-Orbital

Tumors with Osteolysis

Eight cases with osteolysis

With or Without Extra-Orbital

Extension

alone

Two epitheliomas: isodense mass effect in the cone, without ocular lesions. and with exophthalmos. Osteolysis involves the lacrimal bone and the lateral wall of the ethmoid bone. There is no increase in density after the injection of contrast medium. One cholesteatoma which has the same characteristics and occupies the entire po$tcric)r pole of the orbit. One voluminous angioma with exophthalmos: increased density of the eyeball and the cone. with enhancement, and destroying the superior and medial bony contours of the orbit. Two metastases, one from a sympathoblastoma: exophthalmos, isodense mass effect with osteolysis, and no enhancement. Two orbital abscesses: one due to a foreign body (piece of wood) located superior laterally (not seen by CT). The results are limited and misleading: hyperdensity of the cone, with enhancement, and associated with osteolysis due to osteitis. The other abscess complicated an astrocytoma of the optic nerve. The densitometric modifications of the cone in axial sections did not allow diagnosis. Coronal sections (not done) might have provided the proper results. Orbital tumors with regional This group

is rather

an exact

extension

limited

(6 patients)

and comprises:

One orbital mesenchymoma: this patient presents exophthalmos with a hyperdense mass effect of the cone and the eyeball, with enhancement, causing considerable osteolysis, and with extensive involvement of the facial structures and the anterior and middle portions of the base of the skull. One orbital lesion due to chronic lymphocytic leukemia: lesion of the cone, with a hyperdense mass effect, with enhancement, associated with osteolysis and invasion of the facial structures and the base of the skull. One malignant melanoma: mass effect of the cone, extending to the maxillary sinus, and without enhancement.

Orbital

syndromes-CT

analysis

253

of 100 cases

One plexiform neuroma: exophthalmos with deformity and osteolysis of the orbit. A hyperdense mass with enhancement occupies the musculoaponeurotic cone and extends to the facial structures and the base of the skull. One case of Hand Schtiller Christian disease with the same CT characteristics as the plexiform neuroma. One orbito-maxillary epithelioma; post-surgical recurrence in the orbit, extending to the base of the skull and the maxillary sinus (no enhancement).

“SECONDARY”

ORBITAL

(SPREADING

TO THE

SYNDROMES ORBIT)

The study includes 55 cases of tumors of the facial structures, the base of the skull, or the meninges with clinical and/or radiological signs involving the orbit (36 malignant tumors, 19 benign tumors). Malignant

Tumors

Epitheliomas

The tumor most frequently encountered is of course the epithelioma. Twenty-five cases are studied, each presenting orbital invasion, with a definite male predominance (23 cases). The age group most frequently involved is 4&60 years (14 cases) and over 60 years (9 cases). CT shows a partial or complete filling of the sinuses of the face, along with various degrees of osteolysis. In two cases the lesions are severe enough to produce a heterogeneous mass effect with intra-tumoral calcifications corresponding to bone fragments which are partially lysed, and free within the tumor. Thirteen times, the initial lesion is located in the ethmoido-nasal region, 9 times in the maxillary sinus. Lesions in the other locations are much less frequent. Precise analysis of modifications in CT divides these tumors into two groups, depending on the initial lesion. Tumors of ethmoido-nasal origin: 13 cases [14] (Fig. 10). The density of these tumors is generally the same as that of muscle and there is insignificant enhancement. In 8 cases, the patients presented with severe exophthalmos indicating invasion of bony and musculo-aponeurotic structures of the orbit. In every case there is osteolysis and in 7 cases the muscular tissues (temporal, pterygoid and masseter muscles) are altered; disappearance of the peri-

Fig. 10. Left ethmoido-nasal epithelioma. Extensions towards the left orbital cavity, and the temporal and the maxillary sinus. Partial osteolysis of the pterygoid process.

fossa

F. GUIBERT-TRANIER,J. PITON, A. CALABETand J. M. CAILL~

EPiTHELiowa

11 C.I.S Fig. 11. Modality

rthmo’ido.

nasal

cavities

of extension.

EPiTHELiOMAS

-_

‘13

CM.*

Fig. 12. Modality

athmbldo-

nasat

caritirr

of extension

muscular clear outlines along with muscular fusion. This aspect corresponds most frequently with invasion of the pterygoid(s) and the pterygo-maxillary fossa. The types of extension of these tumors are represented in Figs 11 and 12. Tumors of maxillary origin: 9 cases and 3 supplementary cases classified as ethmoido-maxillary (Figs 13-14). Exophthalmos was found in six of these patients. The CT images are, of course, identical to those of the preceding group. However, this group is easily differentiated because of its types of extension (Figs 15 and 16). A comparative study of Figures 11 and 12 shows that; (a) Almost all of the cancers of ethmoidonasal origin lead to maxillary sinus invasion. Nearly half spread to the sphenoid, more than one third reach the nasopharynx, and none reach the infra-temporal fossa and (b) When the initial site is in the maxillary sinus, extension to the ethmoid is not constant, sphenoid lesions are uncommon,

Fig. 13. Epithelioma of maxillary sinus. Extensions toward cavity. with bone destruction. Respect of the pterygo-maxillary goid muscle).

the orbit, the temporal fossa, fossa (see the well delineated

the left nasal lateral ptery-

Orbital syndromes-CT analysisof 100

Fig. 14. Ethmoido

maxillary

255

~SCS

epithelioma. Extension to the left orbital cavity and nasal cavity lysis (left) and respect of the pterygoid fossa (right).

with osteo-

and invasion of the nasopharynx is rare. Finally, these tumors tend to migrate towards the infratemporal fossa. Adenocarcinomas are found most frequently in the anterior ethmoid, and progress locally. Squamous cell carcinomas are found in both the anterior and the posterior ethmoid. They are much more invasive, and contra-lateral and orbital extension is rapid, along with invasion of the musculoaponeurotic cone. There is always a considerable inflammatory reaction, but CT cannot distinguish the inflammation from the tumor.

EPiniuiows

maxalary 9

rmur

EPiniELiot4As:

Cas.5

Figs 15 and 16. Type of extension.

maxillary

Sl”“I

e cas**

F.

256

Metastases

GUIBERT-TRANIER, J. PITON,A. CALABET and J. M. CAILLB

from primary adenocarcinomas

Only four cases of metastatic spread to the orbit were studied (3 women, 1 man). These metastases reach the sphenoid once, the ethmoid twice, and the nasopharynx once. Aside from their orbital extension, these tumors spread by various means. It should be pointed out, however, that in these four cases the sphenoid is invaded. In every case there is osteolysis. Although the musculo-aponeurotic cone was invaded in two cases, clinical exophthalmos was present in only one. CT is not characteristic; in one case, enhancement exists (metastasis from thyroid cancer). Practically speaking, without a known history of neoplasm, it does not seem possible to differentiate an epithelioma from a metastasis. Other malignant tumors These are much less common. group of four malignant tumors

Fig. 17. Meningo-sarcoma.

We observed in children.

two meningiosarcomas,

one chondrosarcoma,

Involvement of the ethmoid, sphenoid, orbital and maxillary geneous aspect. Sphenoid osteitis condensans.

cavities.

Hetero-

and a

Orbital

syndromes-CT

analysis

of 100 cases

251

Meninyiosarcomas (Fig. 17). Both cases concern men in their 50s. The exact origin of the tumor remained undetermined. In CT, these tumors appear very heterogeneous, with a grainy texture due to the free bone fragments within the tumor. The tumors are osteolytic, there is enhancement and considerable extension exists when the diagnosis is made. All the cavities of the face are involved, as well as the ethmoid, the sphenoid, and the nasopharynx. Obvious orbital involvement in these two patients caused exophthalmos in only one. Finally, osteitis condensans of the sphenoid exists in both cases. Chondrosarcoma (Fig. 18). We found only one case of chondrosarcoma in a 50 year old man. Here again, the origin is in the ethmoid and extension to the splanchnocranium and the endocranium is considerable, leading to marked facial asymmetry. The CT image is heterogeneous with a density greater than that of muscle, and with huge hyperdense islets giving a characteristic shattered-glass appearance. As with the preceding tumors, this tumor is enhanced. Obvious involvement of the

Fig. 18. Chondrosarcoma.

Typical

aspect

with osteolysis,

and shattered-glass

appearance.

258

F. GUIBERT-TRANIER, J. PITON,A. CALABET and J. M. CAILLI~

musculoaponeurotic cone is responsible for exophthalmos. The only difference between this and the preceding cases is the absence of osteitis condensans, particularly of the sphenoid. A separate group of4 malignant tumors in children [25]. This consisted of: two boys and two girls, less than 10 years old, 1 malignant esthesioneuro-epithelioma; 1 rhabdomyosarcoma; 1 embryonic tumor and 1 metastasis from a sympathoblastoma. In all cases, the neoformations are enormous and osteolytic. Each concerned the ethmoid (4/4), the sphenoid, the maxillary sinus, and the pterygomaxillary fossa (3/4). Characteristically, there is invasion of the soft tissue with disappearance of the clear outlines. Three tumors present enhancement (rhabdomyosarcoma, embryonic tumor and sympathoblastoma). Twice, the CT image is heterogeneous; calcification of the tumor or lysed bony fragments included in the tumor. Invasion of the orbit exists in each case, and in three there is considerable exophthalmos. Benign Tumors (19 cases) Classijication Meningiomas (Fig. 19). The most frequent of the tumors which invade the orbit originate in the dura mater; 11 cases of meningioma originating in the anterior cranial fossa (ethmoid, jugum, and lesser wing of the sphenoid) [24]. In each case the tumor has a characteristic form with a path of extension along the bony structures: these are plate meningiomas. In this series there is a definite female predominance (8 women, 3 men) and a rather limited age group (9 cases between 50 and 65 years). Invasion of the musculo-aponeurotic cone causes exophthalmos in every case. Secondary bone hypertrophy (8 cases), an important element in the differential diagnosis, and venous pathology of the cavernous sinus are also responsible for the exophthalmos. The density of the tumor is slightly greater than that of muscle. After injection of contrast medium, enhancement exists in 8 of the 11 cases. The type ,of extension is very particular: first towards the ethmoid (7/l 1) and the sphenoid

Fig. 19. Meningioma of the greater wing of the sphenoid. Bone hypertrophy (left) and enhancement after contrast injection. Shows the well delineated margins of the tumor (right).

Orbital syndromes-CT

MENiNCiOMAS

:

259

analysis of 100 cases

HENiNGiOMAS

‘I, ca5a.s

I 1’1cas.5

Figs 20 and 21. Type of extension.

(9/l l), and then towards the rest of the facial structures except for the maxillary sinus (contrary to the malignant tumors). Mucoceles [15] (Figs 20 and 21). Three cases of mucocele in men were found and did not involve a particular age group. In one case the tumor originated in the ethmoid, and twice in the frontal sinus. All of the tumors were accompanied by bone wear and deformation, without obvious osteolysis. Orbital extension in the three cases leads to marked exophthalmos. The density of these tumors is the same as that of the muscular tissue. In every case the tumor spreads toward the ethmoid and the orbit, and once toward the nasal fossa. Juvenile angiojibroma (Fig. 22). A 16 year old male presents with diplopia, decreased visual acuity, and discrete exophthalmos. In CT, a tumor occupies the nasal fossa and the nasopharynx and its density is equal to that of the muscle. The interpterygoid region becomes more rounded, and this deformity is due to wear on the bone by the tumor rather than destruction. Involvement of the ethmoid and the sphenoid includes partial osteolysis. The musculo-aponeurotic cone does not appear invaded and the exophthalmos is due to generalized pressure on the orbit. Injection of contrast medium yields a marked increase in density of the tumor. Esthesioneuro-epitilelioma [20]. In a 65 year old woman, a tumor of ethmoido-nasal origin is responsible for exophthalmos. Its density is the same as muscle. Extension is widespread to the facial structures and the nasopharynx with partial osteolysis. Schwannome. In a 50 year old woman, a tumor originating in the maxillary sinus is discovered. Orbital involvement includes infiltration of the cone, a factor responsible for exophthalmos. Extension to the facial structures and the base of the skull is widespread. The tumor is isodense with respect to muscle, and is enhanced after injection of contrast medium. There is partial osteolysis and there are no distinguishing characteristics. Fibrous dysplasia We observed two cases of fibrous dysplasia in patients between the ages of 20 and 40 years. These tumors present as a more or less diffuse heterogeneous hyperdense zone of the orbital margin and of the base of the skull. In one case there is exophthalmos, but without modification of the musculo-aponeurotic cone. The image is characterized by involvement of the bone and not of the adiacent soft tissues which are pushed aside. Together, these lesions deform the entire facial structure. DISCUSSION Using the data obtained from the study of these 100 cases, we have tried to define the role of CT in the diagnosis and evaluation of orbito-facial tumors and its relationship to other exploratory examinations.

260

F. GUIBERT-TRANIER, J. PITON,A. CALABET and J. M. CAILLB

Fig. 22. Juvenile angiofibroma. Mass of the nasopharynx enlarging the interpterygoid region extending toward the anterior part of the pterygoid fossa. Enhancement (top). Extension to the endocranium and the orbital apex (bottom).

Orbital syndromes--CTanalysisof 100 cases A Separate

Group of Ocular and Orbital Tumors

Ocular tumors [4, 22, 303

CT does not determine the layer of the eye (sclera, choroid layer, or retina) from which the tumor develops. CT characteristics are nonspecific (density-situation-enhancement). Only the presence of intra-tumoral calcification is specific of retinoblastoma. These calcifications can be demonstrated earlier with CT than with conventional roentgenograms. Thus, CT permits the diagnosis of an intra-ocular mass, just as do fundoscopic examination and echography. Ultrasonic examination has the advantage of not irradiating the lens, but it is not as precise as CT in evaluating possible extension to the orbit and especially the relationship to the optic nerve. Finally, CT constitutes the least aggressive means of searching for intracranial extension. According to some authors (l), the first step in exploring an ocular tumor is echography (10). If the tumor is benign, CT is necessary only in the case of a phacoma in search of an intracranial lesion. If a malignant tumor is highly suspected, CT permits an evaluation of its extension and the determination of a therapeutic plan. Orbital tumors [2Y]

Along with echography, CT is the least traumatic of the exploratory methods of examination of orbital tumors [S]. Its chief drawback is that it irradiates the lens. This factor should be considered when overlap sections are performed and are repeated during successive examinations. Otherwise, CT is almost completely innocuous, except for the risks associated with the injection of iodine contrast medium and general anesthesia when it is necessary (agitated patients and children). The diagnosis of intra-orbital mass; several authors [3, 13,21,23] have evaluated the value and reliability of CT compared to other means of orbital exploration: echography, phlebography, carotid angiography and conventional tomography. As a result of these studies, CT is equivalent to echography in the diagnosis of large tumors. However, CT is clearly superior concerning small tumors of the orbital apex. In addition, CT is much more precise than echography in evaluating the volume, limits and relationships of the tumors, principally with the optic nerve. In determining the pathological diagnosis, CT has made a definite contribution concerning two affections. Endocrine exophthalmos, especially in unilateral, euthyroid cases [6]. In the majority of cases, CT eliminates the diagnosis of orbital tumor and provides the now well-known characteristic image; muscular hypertrophy which often predominates in the medial rectus, with enhancement [17,21,35]. Inflammatory pseudotumors whose CT images are characteristic: thickening of the layers of the eye [ST],tumefaction of the musculo-aponeurotic cone. and marked enhancement after injection of contrast medium [18]. Varicose ophthalmic veins are easily diagnosed with CT. This is the only remaining indication of orbital phlebography which confirms the diagnosis. For all other orbital tumors, the diagnosis of the type of tumor is difficult regardless of the method of exploration. Echography permits the diagnosis of intra-orbital mass, while CT determines the volume and the relationships of the tumor. CT criteria, before and after contrast medium, lack specificity. except possibly in the case of orbital angiomas which are heterogeneous and slightly enhanced. The origin can sometimes be determined, thus yielding a diagnosis (ophthalmic varicosity, meningioma of the optic nerve). CT, like conventional tomography, evaluates the state of the bony structures. Enlargement of the orbit, without osteolysis, seems to be in favor of a slowly progressive tumor, thus presumably benign (phacomas, angiomas). Osteolysis, on the other hand, is more indicative of malignancy, but is also seen with infectious lesions (two orbital abscesses) and during the progression of a cholesteatoma and of an orbital angioma. Finally, CT is the best means of detecting an endocranial tumor (angiomas, phacomas) or extension (meningiomas, malignant tumors). Orbital phlebography can only locate the tumor. The diagnosis of the type of tumor is only possible in the case of ophthalmic varicosities. Pretherapeutic

evaluation

and surveillance

CT has brought considerable progress to the pretherapeutic evaluation of malignant tumors and in the surveillance during and after treatment. However, one drawback of CT is its inability to differentiate inflammatory tissue from neoplasia. This presents a problem when checking for recurrence.

262

F. GUIBERT-TRANIER, J. PITON, A. CALABETand J. M. CAILL~

Thus, CT occupies an important position in the hierarchy of orbital tumor explorations. Like echography, it permits the diagnosis of an orbital mass. CT demonstrates the existence of osteolysis as well as tomography does. But CT alone can determine, completely innocuously, and in a manner more accurate than carotid angiography or orbital phlebography, the volume, relationships, and extension of the tumor. In practice, CT is indispensable for any exophthalmos or orbital symptom. In certain cases, diagnosis and a therapeutic decision can be made based solely upon CT [33]. In other cases, CT cannot determine the type of lesion, but orients the choice of complementary investigations. Facial Tumors Which Have Spread To The Orbit CT is used in two circumstances: when determining the etiology of an orbital syndrome and when evaluating the extension of a facial tumor. Our study shows that malignant tumors lead to orbital extension (65%) more frequently than benign tumors (35%). CT has provided several elements in the exploration of these tumors: first, it is nontraumatic, except for the risks of general anesthesia, the injection of contrast medium, and irradiation of the lens, all of which have already been mentioned and second, additional diagnostic elements, compared to other exploratory methods. The diagnosis of a mass: CT permits the demonstration of the tumor syndrome which, in the facial structures, produces a filling of the sinuses. CT gives a precise analysis of the volume, outline, and usually the origin of the tumor, except very advanced lesions where the origin cannot be determined. The pathological diagnosis: according to our study, we propose characteristic aspects of malignant and benign tumors. Malignant tumors

Studying densities furnishes no characteristic elements. The presence of intratumoral calcifications can indicate a chondrosarcoma, but usually they are due to intratumoral fragments of lysed bone. Density modifications after the injection of contrast medium has no specificity. This correlates with the work of several authors [7,19,31]. However, analysis of the bone structure is very interesting. In fact, osteolysis seems highly suggestive, if not characteristic, of a malignant tumor. In our series osteolysis was observed in every case of malignancy. Generally, the limits of the tumor are imprecise. The more a tumor is invasive, the more it suggests malignancy. A contralateral lesion is frequent with malignant tumors. Benign tumors

Here too, studying densities is of little interest. Sometimes modifications after the injection of contrast medium suggest an etiological diagnosis (meningioma, juvenile angiofibroma) [36]. The limits of the tumor are clearly outlined by the air in the sinuses. Analysis of the bone distinguishes between benign and malignant tumors; benign tumors do not destroy bone-tissue. A benign tumor can wear away, deform, or widen the bone structure but only rarely does it break up the bone (uncertain in our case of angiofibroma). The bone can be widened and condensed in the case of a meningioma [9]. Fibrous dysplasia gives this same image, but is differentiated upon injection of contrast medium [34]. Finally, there is less extension with benign tumors, but this is not a dependable sign. Thus CT allows us to differentiate between malignant and benign tumors in the majority of cases. This determination is based principally on the existence or absence of osteolysis. In certain cases, CT provides the etiological diagnosis. The pretherapeutic evaluation

CT is frequently part of the pretherapeutic evaluation of a tumor whose histology is already known. CT furnishes an estimate of the volume and the extension of the tumor [ll, 121; towards the face and the orbital cavities and towards the pterygo-maxillary fossa. The state of this fossa is carcinologically primordial in determining the operability of a tumor. Its invasion is represented by

Orbital syndromes-CT

analysis of 100 cases

263

the existence of osteolysis of the pterygoids and the disappearance of the hypodense fatty outlines which no longer distinguish the different muscles. This is seen as a filling of the pterygo-maxillary fossa. Towards the infra-temporal fossa, the disappearance of the fatty outlines again affirms extension to the infra-temporal fossa. Towards the endocranium, this extension is often easily diagnosed due to osteolysis and a mass effect whose density is different from that of the brain. However, in certain cases, injection of contrast medium is required in order to affirm the endocranial lesion, and especially to determine its limits [31].

Therapeutic program Evaluation furnishes the lance during readjustment

of extension is of major interest in establishing a therapeutic irradiation program. It target volume, the type of treatment, the incidences and the dosimetric curves. Surveiltreatment can show a shrinking of the tumor at mid-treatment and thus enables of the program to the new target volume by decreasing the sizes of the fields.

Post-therapeutic surveillance Because it is harmless, CT is the ideal surveillance method. It shows the decrease in tumor volume after radiotherapy and the completeness or incompleteness of surgery when possible, and the quality of bone reconstruction. It also demonstrates local or regional recurrence. It remains difficult, however, to distinguish between neoplasia and inflammatory or infectious tissue. The role of’CT in the exploration of tumors of the face Certain authors [3,13,23] have compared CT results with those of conventional tomography. In 80% of the cases, CT performs at least as well as tomography. Conventional tomography permits the diagnosis of an opacity in a facial sinus, as well as the visualization of osteolysis, but it cannot demonstrate extension to the orbit, the endocranium, or the pterygo-maxillary fossa. Also, tomography exposes the patient to a considerably higher level of irradiation than CT. On the other hand, CT has the advantage of simultaneously and precisely visualizing soft tissue and bone. It demonstrates invasion of the endocranium, the orbit, and of the pterygomaxillary fossa without complementary exploration. Analysis of bone structure is probably not as good as in conventional tomography, but 3 and 6 mm sections and increasing spatial resolution permit an analysis which generally is satisfactory. Concerning angiography, the same indications exist as before CT. In certain cases complementary diagnostic elements are obtained, and angiography demonstrates the vascular origin and the type of vascularization of a tumor. In practice, the diagnostic procedure begins with plain skull roentgenograms, followed by tomography and then CT. The question is whether or not conventional tomography is still needed in the diagnosis and exploration of facial tumors, and if it will be replaced by CT. The injection of contrast medium is debatable. In fact, it usually furnishes no additional elements for the etiological diagnosis. Its value seems to be limited to the demonstration of intracranial extension and an evaluation of its limits. CONCLUSION CT plays an important role in the exploration of orbitofacial tumors. Its application leads to less frequent use of other examinations which are more aggressive and more irradiating. However, CT does not always permit an etiological diagnosis since the CT criteria of most tumors are nonspecific. Nonetheless, one can generally conclude whether a tumor is benign or malignant. On the other hand, CT has transformed the pretreatment evaluation and the treatment program of malignant tumors, as well as post-therapeutic surveillance. Thus, the role of CT is to diagnose a facial tumor, and to evaluate its volume and extension, factors needed to determine the treatment which will be instituted after a histological diagnosis has been made.

264

F. GUIBERT-TRANIER,J. PITON, A. CALABET and J. M. CAILLB

REFERENCES I M. L. Aubin and J. Vignaud. Computerized tomography of the eye, A study of 62 pathologic cases, ~eurorc~diohg~ 16, 456-457 (1978). 2. D. Bal&riaux-Waha, U. Nortelmans. M. G. DuPont, G. Terwinghe and L. Jeanmart, The use of coronal scans for computed tomography 01’the orbits, Neurorcldio/o~/~ 14, 89-96 (1977). 3 H. Becker. Grau Holger. H. Hacker and K. W. Ploder, The base of the skull: a comparison of computed and conventional tomography, J. (.IJ!JI/~.~~\r~.sr.Tomog. 2, I I3 I I8 (1978). 4. M. E. Bernardino, J. Dan/rgct-. Sue Ellen Young and S. Wallace, Computed tomography in ocular neoplastic disease, Am. .f. Roentgenol. 131, I I I I I3 I 1978). 5 M. E. Bernardino, R. D. Zimmermann, C. M. Citrin and D. 0. Davis, Scleral thickening: a CT sign of orbital pseudotumor, Am. J. Roeqrrwl. 129, 703-706 (1977). 6 J. Brismar, K. R. Davis, R. L. Dallow and G. Brismar, Unilateral endocrine exophthalmos. Diagnostic problems in association with computed tomography, Neurorudiology 12, 21-24 (1976). 7 J. M. Caillk, Ph. Constant, J. L. Renaud-Salis and A. Dop, CT studies of tumors of the skull base, facial skeleton and Computerized Tomogr. 1, 217-224 (1977). nasopharynx, x F. C. Chu, Radiological methods of studying the orbit, Computerized Tomogr. 1, 45-50 (1977). 9 L. E. Claveria. D. Sutton and B. M. Tress, The radiological diagnosis of meningiomas, the impact of EMI Scanning. Br. J. Rodiol. 50, 1% 22. ( 1977). 10 D. J. Coleman. D. U. Abramson, R. L. Jack and L. A. Franzen, Ultrasonic diagnosis of tumors of the chordid, Arc.h.5 Opl1rulmol. 91, 344354 (1974). de I’enctphale, de la base du crBne et du 11 Ph. Constant, J. M. Caillt and A. Dop, It&r&t d’une itude tomodensitomttrique massif facial en incidence semi-axiale, J. Neuroradiol. 3, 185-191 (1976). des tumeurs des voies optiques antkrieures et de I’orbite 12 Ph. Constant, A. Dop and J. M. CaillB, Etude densitombtrique (Acta Scanner), Bull. Sot. Ophtal. France 11 (1976). of ultrasonography computerized tomography (EM1 Scan) and radiographic techniques in 13. R. L. Dallow, Comparison evaluation of exophtalmos, Trans. Am. Acad. Ophthal. Otolnrytig. 81, 305-321 (1976). Possibilitt d’exCrtse et de rkparation chirurgicale, Neurochiruryie 18, 14. P. Derome et al., Les tumeurs sphtno-ethmdidales. Suppl. I (1972). Mucoceles with intracranial and extracranial IS. F. Diaz, R. Latchow, A. J. Duvall, C. A. Quick and D. L. Erickson, extensions. Report of two cases, J. .Nwro.sur~/. 48, 284-2X8 ( 1978). en pathologie tumorale de la 16. A. Dop, Ph. Constant, J. L. Rennud-SalIs and J. M. &ill&, In&it de la tomodensitomitrie base du crine et du massif facial, J. Nrurortrdiol. 3, 193-214 (1976). 17. D. Enzmann, W. H. Marshall. A. R. Rosenthal and J. P. Kriss;Computed tomography in graves’ophtalmopathy, Rtrtliology 118, 615-620 (1976). IX. D. Enzmann, S. S. Donaldson, W. H. Marshall and J. P. Kriss, Computed tomography in orbital pseudo-tumor (idio. pathic orbital inflammation), Rodio/o~/~ 120, 597-601 (1976). 19. C. G. Gonsalves, T. D. R. Briant and W. M. Harmand, Computed tomography of the paranasal sinuses, nasopharynx, and soft tissues of the neck, Computerized Tomogr. 2, 271-278 (1978). anatomique B I’ttude des tumeurs nerveuses de la face et du cou, Tumeurs 20. Y. Guerrier and B. Guerrier, Introduction Nerveuses ORL et Ceruicofuciu/es. Actual&&s de Carcinologie Cervicofaciale. Coordonnateur J. Leroux-Robert, pp. I-5, Masson ed. (1977). J. Lester and H. Fledelius, Computed Tomography of orbital lesions. A radiological study of 141 cases, 21. C. Gyldensted, Nrurortrdioloyy 13, 141-150 (1977). tomography of the orbit using thin sections, Semin. Roentyenol 7, l37- I46 22. S. K. Hilal and S. L. Trokel, Computerized (1977). entre la tomographie pluri-directionnelle et la 23. G. Korach, J. Vignaud, A. Palmieri and M. L. Aubin, Comparaison tomodensitomCtrie dans l’exploration de la base du crsne, J. Radiologie 60, 159-168 (1979). Les mtningiomes extracrhniens, Tumeurs Nerveuses ORL et Ceroicofaciales, Actualit& de carcinologie 24. J. Leroux-Robert, cervicofaciale. Coordonnateur J. Leroux-Robert, pp. 157-176, Masson ed. (1977). des tumeurs ORL et cervicofaciales chez l’enfant. Leurs difficult& 25. J. Leroux-Robert and J. de Brux, Histopathologie de carcinologie cervico-faciale. Coortventuelles d’interprttation, Les Tumeurs Ceraico-Faciales de I’Enfanf, Actualitts donnateurs J. Leroux-Robert, J. Bourguet, pp. 1 l-28, Masson ed. (1978). and B. S. Wolf, Delineation of lesions of the base of the skull by computed tomography, Radiology 124, 26 H. Nakagdwa 75-80 (1977). fossa, Am. J. Roentgenol 132, 389-394 (1979). 21 A. G. Osborn, Radiology of the pterygdid plates and pterygopalatine 2x. U. Salvolini, E. Cabanis, A. Rodallec, F. Menichelli, U. Pasquini and M. T. Iba Zizen, Computed tomography of the optic nerve. Part I. Normal results. Part II. Size and shape modifications in papilledema, J. Comput. trssist. Tomogr. 2, 141&1.55 (1978). assisted tomography in 90 cases of exophthalmos, J. Cornput. 29. U. Salvolini, F. Menichelll and U. Pasquini, Computer us.&., Tomogr. 1, 81-100 (1977). 30. J. A. Shields and L. E. Zimmerman, Lesions simulating malignant melanoma of the posterior uvea, Arch OphthalmoL 89, 466-471 (1973). 31. R. Tadmor and P. F. J. New, Computed tomography of the orbit with special emphasis on coronal sections. Part 1. Normal anatomy. Part II. Pathological anatomy, J. Comput. assist. Tomogr. 2, 2444 (1978). 32. W. Van Damme, P. Kossmann and C. Wackenheim, A standardized method for computed tomography of the orbits, Neurorudiology 13, 139-140 (1977). 33. M. Vermess. B. F. Haynes. A. S. Fauci and S. M. Wolf, Computed assisted tomography of orbital lesions in Wegener’s granulomatosis. J. Cornput. c/.,\isr. Tomo(qr. 2, 45-48 (1978). 34. H. Vogelsang. L. StBppler and G. Thiele, Fibrous dysplasia of the skull. Roentgenologlc, computer tomographic and scintigraphic study, Fort&r. C;eh. RiintgSrruhl. NuklMed. 128, 253. 257 (197X). 35. A. Wackenheim, W. Van Damme, P. Kossmann and B. Rittighoffer, Computed tomography in ophthalmology. Density changes with orbital lesions, Neurorndiology 13, 135-138 (1977).

Orbital

syndromes-CT

analysis

265

of 100 cases

36. M. A. Weinstein, H. Levine, P. M. Duchesneau and H. M. Tucker. Diagnosis of juvenile angiotibroma by computed tomography, Rtrdio/o