TUMOUR OF THE OPTIC CHIASMABY

S. N. JAVETT and ERIC SAMUELJohannesburgh, South Africa

Tumours arising in the small area at the base ofthe brain between the optic chiasma and cerebralpeduncles are common and include meningiomas,suprasellar and pituitary neoplasms, aneurysm ofthe circle of Willis, and chiasmal arachnoiditis withcyst formation. Tumours arising in the opticchiasma and nerve sheaths, however, are veryuncommon. In all these conditions, visualsymptoms may obtrude to a degree that rendersclinical differentiation difficult. In the case ofchiasmal glioma here reviewed, diagnosis was muchsimplified by the characteristic radiological features.

Case ReportA bright and alert male child aged five and a half

years was referred because of defective vision in theright eye. There was nothing relevant in the pasthistory. He was the elder of two children ofnormalparents. Pregnancy and labour were normal andthe birth weight was 6 lb. 5 oz. He had beenartificially fed from birth, he thrived and developedwell, and all the milestones were normal. At theage of fifteen months he had a sore throat with anaccompanying convulsive episode attributed to highfever. Three months later he contracted measlesand again exhibited two tonic convulsions inassociation with a high temperature. Unconscious-ness lasted two minutes on each occasion. Thesefebrile convulsions are in keeping with the corticaldysrhythmia which was found later in the electro-encephalogram, and which was presumably of theinherited type as both his father and younger sisterhad convulsions under similar circumstances. Hehad remained perfectly well until two and a halfmonths before admission, when he complained of aslight headache, frontal in distribution, worse in theevening and improving in the morning. He hadtwo further headaches of similar nature. Theparents consulted an ophthalmologist, who reportedthat the child was blind in the right eye, the leftbeing normal. The child never complained thathe could not see, nor had his school mistresssuspected defective vision. There was no nausea,vomiting, polyuria, polydipsia, or loss of weight.On examination it was found that the child's

faculties were normal. He was not ill, nor in anydiscomfiture. There was no jaundice, cyanosis,dyspnoea, or oedema. Temperature, pulse rate, andrespiration, heart, lungs, and abdomen were allnormal. Blood pressure was 100/60 mm. Hg.

There was no external evidence of neurofibromatosis.The child appeared normally proportioned-weight 37 lb., height 42 in., span 42 in., symphysisto vertex 22 in., symphysis to ground 20 in., skullcircumference 20 5 in. No neck rigidity ormurmurs on auscultation of the skull, and noexophthalmos or ptosis were noted. All the cranialnerves except the second appeared normal. Centralvisiopn in the right eye was absent, but on confronta-tion tests movements were perceived in the temporalfield. Consensual and light reflexes were present,but the contraction of the right pupil to light wasnot as full as the left nor as well maintained. Theoptic disc was white, its edges sharply defined andthe vessels normal. Vision in the left eye was full,but the disc was paler than normal, especially ofthe nasal half. Accurate plotting of the visualfields was impossible because of the child's age.The eye findings were interpreted as a large centralscotoma of the right eye with well marked opticatrophy and commencing atrophy of the left disc.The rest of the cranial nerves and central nervoussystem were normal.LABORATORY STUDIES. The blood count was:

haemoglobin, 13 4 g.; colour index, 0 99; redblood cells, 4,340,000; white blood cells, 7,900 per100 c.mm. of blood; polymorphs, 51 per cent.;monocytes, 4 per cent.; lymphocytes, 43 per cent.;eosinophils, 2 per cent.The sedimentation rate was: 15 mm. in the first

hour. The blood Wassermann reaction wasnegative. The specific gravity of the urine was1024, and there was no albumin or sugar. TheMantoux (1/1000) test was negative.The glucose tolerance test was: fasting, 95 mg.

per cent.; after ingestion of glucose, 70 mg., 80 mg.,90 mg., 50 mg. at half-hourly intervals. Thisrepresents doubtful increase of tolerance to glucose.A radiograph of the wrist joint showed a normal

ossification index.Cerebrospinal fluid pressure was 110 mm. with

no block (one lymphocyte; no bacteria; protein70 mg. per cent.; chlorides 720 mg. per cent.;sugar 60 mg. per cent.; Wassermann reactionnegative).

Eight hours after lumbar puncture the childcomplained of severe pain in the back and right hipwhich radiated down the back of the right leg.The pain persisted for two days. It then ceasedbut was replaced by an attack of headache andvomiting which lasted a further three days. The

248

by copyright. on June 16, 2020 by guest. P

rotectedhttp://adc.bm

j.com/

Arch D

is Child: first published as 10.1136/adc.22.112.248 on 1 D

ecember 1947. D

ownloaded from

TUMOUR OF THE OPTIC CHIASMApost lumbar puncture episode was undoubtedly ofsome significance even though cerebrospinal fluidpressure was normal.RADIOGRAPHY OF THE SKULL. The lateral radio-

graph of the sella turcica and the region of the sulcuschiasmaticus (Plate Vlla) revealed a characteristicenlargement of the anterior part of the sella turcicawith an excavation of the under surfaces of bothanterior clinoid processes. These changes werecaused by a pressure atrophy, and the bone in theaffected region was thinned. A lateral tomograph(Plate VIIb) of the sella turcica demonstrated thesechanges even more clearly.Rhese Goalwin view (Plates VIIc and d) revealed

an increase in the size of both optic foramina, theright more than the left. It is interesting to notethat on the left side, the less affected side, the marginof the optic foramen was sclerosed, suggesting thatin the early stages irritation may lead to sclerosiswhilst later pressure causes atrophy of the foraminalmargin.An electroencephalogram with monopolar leads

from both hemispheres showed rather erraticrecordings. Mixed frequencies of 1-10 per secondwere present. It was concluded that there wascortical dysrhythmia without focalization; there wasno evidence of epilepsy.

Consideration of the clinical findings pointed toa space-occupying lesion in the region of thepituitary fossa. The radiographs more accuratelylocalized the lesion to the region of the sulcuschiasmaticus of the sphenoid bone and demonstratedthat the floor and the posterior clinoid processesof the sella turcica were intact. In addition, therewas enlargement of both optic foramina, indicatingthat both optic nerves were involved. A diagnosisof chiasmal glioma was made and an exploratoryoperation was advised to verify the diagnosis.Prefrontal craniotomy was undertaken by Dr. R.Krynauw, who reported: ' After the optic nerve

had been stripped, a large pink tumefaction aboutthe size of a pigeon's egg was encountered. It wascontinuous with the chiasma and extended back-wards along the optic tracts. Removal of thislesion would be technically impossible or nearly so.'Three months after the operation the generalcondition of the child was unchanged. The righteye was totally blind.

CommentChiasmal glioma is essentially a condition of

childhood. It arises in the chiasma or adjacentwall of the third ventricle, spreading forwards toinvolve the nerve even as far as the papilla. Intra-cranial involvement of the optic nerve is much rarerthan intraorbital involvement. The growth is slowand may not cause death for many years. Davis(1940), reviewing the literature since 1876, foundthirty-eight cases associated with neurofibromatosis,in twelve of which there was an hereditary element.Vision is involved early, and marked deteriorationor even blindness may be present before symptoms

of cranial hypertension manifest themselves. Visualaffect is bizarre, optic atrophy and central scotomatending to appear rather than bi-temporal orhomonymous hemianopia. Where the nerve headhas been invaded, exophthalmos may be present.In many of the reported cases endocrine symptomshave been absent, though Ford states that poly-dipsia, polyuria and-obesity, consequent on pressureon the hypothalamus, are common. The radio-graph shows a bulging or erosion beneath theanterior clinoids; enlargement of the optic foraminacan often be observed.

Differential diagnosis. Other conditions involvingthe optic chiasma require consideration in thediagnosis, namely craniopharyngioma, pituitarytumour, aneurysm of the circle of Willis, suprasellarmeningioma, and chiasmal arachnoiditis with cystformation.CRANIOPHARYNGIOMA. This is a not infrequent

tumour of childhood, constituting roughly one-seventh of all intracranial neoplasms at this age, andis the most important condition requiring differentia-tion. The subject has been well reviewed byIngraham and Scott (1946), who point out that, incontradistinction to chiasmal glioma, signs ofintracranial hypertension such as headache andvomiting precede visual disturbance. The lattertakes the form of lower quadrantic defects proceed-ing to bi-temporal hemianopia. Optic atrophy mayoccur. Evidence of acute hydrocephalus can beestablished by ventriculography. Pressure on thehypophysis commonly leads to arrested skeletaldevelopment, whilst hypothalamic signs are rare.In the radiograph suprasellar or intrasellar calci-fication is present in 75 per cent. of cases. Separa-tion of sutures, convolutional atrophy, erosion ofposterior clinoids, enlargement and distortion ofthe floor of the sella may also be noted in theradiograph. Pressure atrophy of the anteriorclinoid processes is seldom marked, and whenmarked generally involves the superior surface ofthe anterior clinoid process in contradistinction tothe chiasmal glioma (Plate VILe).PrrurrARY NEOPLASM. The age factor operates

heavily against a diagnosis of pituitary neoplasm,which is practically unknown under the age of tenyears. Here, endocrine disturbance is to theforefront. Reference has already been made to theradiological location of the maximal pressurechanges in chiasmal glioma as affecting the anteriorpart of the sella turcica with little. involvement ofthe floor or post-clinoid processes. A pituitarytumour throws the main stress of pressure atrophyon the floor and post-cinoid process (Plate VHf).A radiological appearance of an eroded anteriorclinoid process without involvement of the floor orpost-clinoid process is against the diagnosis of aprimary pituitary neoplasm.MENINGIOMA. The age factor applies similarly

to meningioma, commonly seen in middle-agedadults. Meningioma arising near the body andlesser wing of the sphenoid generally produces some

249

by copyright. on June 16, 2020 by guest. P

rotectedhttp://adc.bm

j.com/

Arch D

is Child: first published as 10.1136/adc.22.112.248 on 1 D

ecember 1947. D

ownloaded from

250 ARCHIVES OF DISEASE IN CHILDHOOD

sclerosis of the adjoining bone, and atrophy is lesscommon. ,ANEURYSM. This, too is not common in children.

Associated palsies of third, fourth, and sixth cranialnerves may be present in addition to the chiasmalsyndrome. Calcification may be detected byradiograph in the wall of the aneurysm, and theclinoids may show localized erosion. Angiographyis conclusive.

ARACHNOIDITIS. This is usually the sequal oftrauma and is unaccompanied by endocrine dis-turbance. Plain radiography is negative butencephalographic studies have shown characteristicappearances.

SummaryA case of chiasmal glioma is described and the

clinical and radiological features discussed. A

chiasmal syndrome in the first decade of life,,withthe radiological features of enlargement of bothoptic foramina, erosion beneath the anteriorclinoid processes, and enlargement of the sulcuschiasmaticus is almost diagnostic of this condition.

REFERENCES

Davis, F. A. (1940). Arch. Ophthal. N.Y., 23 (N.S.),735 and 957.

Ford, F. R. (1945). Disease of Nervous System inInfancy, Childhood and Adolescence. 2nd Edition,p. 803. Springfield, Illinois.

Ingraham, F. D. and Scott, H. W. (1946). J. Pediat., 29,95.

Pendergrass, E. P. and Perryman, C. R. (1946). Amer.J. Roentgen., 56, 279.

(For illustrations to this article see Plate VII, p. 259.)

by copyright. on June 16, 2020 by guest. P

rotectedhttp://adc.bm

j.com/

Arch D

is Child: first published as 10.1136/adc.22.112.248 on 1 D

ecember 1947. D

ownloaded from

TUMOUR OF OPTIC CHIASMA BY S. N. JAVETT AND ERIC SAMUEL

(a)-Lateral localized view of sella turcica; showsexcavation beneath anterior clinoid processes and pressureatrophy of floor of sulcus chiasmaticus. The sella turcicabehind this area is unaffected.

(b)-Tomographic film taken at 5 c.m. in the lateralposition. The changes in the bony walls of the sulcuschiasmaticus can be clearly seen.

Rhese Goalwinview of (c) leftoptic foramen,to demonstrateenlargement ofoptic foramen;and (d) rightoptic foramen, toshow massive en-largement of thatstructure withthinning of sur-rounding bonywall.

(e)-Lateral radiograph in a case of cranio- (f)-Lateral radiograph from a case of apharyngioma, for comparison. Note erosion of chromaphobe adenoma of the pituitary. Noteupper surface of anterior clinoid processes, and the generalized enlargement of pituitary fossa, andcalcification. especially the manner in which the main stress falls

on the posterior clinoid processes.PLATE VII

259by copyright.

on June 16, 2020 by guest. Protected

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.22.112.248 on 1 Decem

ber 1947. Dow

nloaded from