Journal of Neurology, Neurosurgery, anid Psychiatry, 1973, 36, 592-595

Dumb-bell neurinoma of the hypoglossal nerve1

A.D. BARTAL, M. M. DJALDETTI, E. M. MANDEL, AND M. A. LERNER

From the Departmenzt of Surgical Neurology, Ichilov Hospital, Tel-Aviv Medical Center, and Departments ofInternal Medicine 'B' and Radiology, Hasharon Hospital, Kupat Holim, Petah Tiqva Municipality, and Tel-

Aviv University Medical School, Israel

SUMMARY A unique case of dumb-bell neurinoma of the hypoglossal nerve is presented. The im-portance of hemiatrophy of the tongue is stressed for early diagnosis of the lesion. The myelocisterno-gram is the single most important contrast study confirming the intracranial extension of the tumour.Total dissection of the tumour capsule may not be feasible in all cases.

Neurinomas of the hypoglossal nerve are rareand have attracted sporadic attention. In 1967,Ignelzi and Bucy reported on a patient and re-viewed nine additional cases of intracranialhypoglossal neurofibromas from the literature.The following case appears to be unique becauseof the intra- and extracranial growth of thetumour. The appearance almost eight yearspreviously of hemiatrophic deviation and fibrilla-tions of the tongue should have been recognizedas an important diagnostic sign.

CASE REPORT

This 36 year old male was admitted urgently to theNeurosurgical Department of Tel-Aviv MedicalCenter on 14 March 1971, because of severe head-aches, vomiting, dizziness, blurred vision, bilateralpapilloedema and imbalance of gait. He had beenadmitted to another hospital three weeks earlierwith a diagnosis of viral encephalitis or hypertensiveencephalopathy.

Eight years before his admission atrophy of theleft side of the tongue was noted on a routineexamination for sore throat. One year later he startedcomplaining of headaches, and blood pressure of200/140 mm Hg was found. He was treated withreserpine, methyldopa, chlordiazepoxide, and fruse-mide. Repeated examinations during the succeedingyears revealed no cause for the vascular hypertension.He was a physically fit, athletically built man with

a left torticollis and marked protective rigidity of theneck. He walked on a broad base and tended to veer1 This work was supported by a research grant from the RofeiHolimr Foundation, New York, to the Judith Herman (Leibovits)Neurosurgical Brain Cancer Research Unit.

to the left and the stance was unsteady, worse witheyes closed. There was tenderness in the left retro-auricular region and a mass was felt in the neckunder the left maxillary angle. Below the bulgingtonsilar recess a hard non-pulsatile mass was felt onbimanual palpation.A fine horizontal nystagmus was noted on left

lateral gaze with the slow component to the left.The pupils were normal. There was bilateral papill-oedema with markedly engorged veins and numeroushaemorrhages, punctate exudates, and arteriovenousnipping of the retinal vessels. No involvement ofcranial nerves V, VI, VII, VIII, and IX was foundbut a mild hoarseness was noted. Asymmetry of theshoulder girdle with drooping of the left side wasseen but there was no noticeable atrophy of the leftshoulder muscle group.Movements of the upper and lower extremities,

muscle tone, and the reflexes were symmetrical.The blood pressure was 160/100 mmHg, the pulse

rate 80 per minute, and the electrocardiogramshowed flattened T-waves, signs of left heart hyper-trophy, left axis deviation, and a suspicion of aposterior wall ischaemic lesion. The electro-encephalograph (EEG) showed 2 to 3 Hz slow waves,predominantly in the right frontal region, over abackground of a generally disturbed record.

RADIOGRAPHIC INVESTIGATIONS In the axial projec-tion of the skull the medial edge of the cervicalmass produced an inward bulge of the pharyngealwall. The bony abnormalities were fully appreciatedonly by laminography: the left occipital condyle,in both anteroposterior (Fig. 1) and lateral projec-tions (Fig. 2a and b) was found to be widely cavitatedas a result of concentric widening of the hypoglossal

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Dumnb-bell neurinoma of the hypoglossal nerve

FIG. 1. Anteroposterior tomography shows the defectof the bony structure of the left occipital condyle(arrow).

FIG. 3. Cisternomyelogram delineating the retro-clinoid component of the tumour.

FIG. 2. (a, top) Lateral tomography, base of skull,shows a normal right lateral tomogramfor comparison.(b, bottom) The 'blown out' hypoglossal canal exca-vates completely the left occipital condyle and eruptsinto the jugular foramen.

canal. Hypoglossal neurinoma was diagnosed onthis basis.The intracranial extension of the lesion was de-

lineated by the cisternomyelogram (Fig. 3), whilethe cervical component of the neurinoma displacedthe internal and external carotid arteries forward(Fig. 4); only a fine capillary blush was apparent.The left vertebral artery was displaced upwardsand posteriorly.

OPERATION At left suboccipital craniectomy underendotracheal anaesthesia the dura mater was foundto be extremely tense. After incision of the duramater and elevation of the left cerebellar lobe, agrey-white tumour mass was uncovered. Blood ves-sels and cranial nerves IX, X, XI were seen tenselystretched over it. Dissection was carried out withthe use of optic magnification. Firm adhesions to the

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A. D. Bartal, M. M. Djaldetti, E. M. Mandel, and M. A. Lernier

FIG. 4. Selective internal carotid angiogram. Anteriorbowing of the artery over cervical component oftumour.

left anterolateral medulla were encountered, andalthough the major part of the capsule was excised,the medial part, adherent to the medulla, was leftbehind. Tracheostomy was performed before extuba-tion and was closed after two days.A month later dissection of the tumour in the

neck was performed under endotracheal anaesthesia.The anterior border of the sternocleidomastoidmuscle was exposed and a 7 cm tumour with a

smooth glistening capsule was dissected out up tothe base of the skull. Histological examination ofboth tumours was typical of an Antoni type Ineurilemomma.During the postoperative period the suboccipital

craniectomy bulged and repeated lumbar puncturewas necessary. To obviate postoperative hydro-cephalus, an atrioventricular shunt was introducedand the patient's condition improved dramatically.Neither the hemiatrophy of the tongue with fascicu-lations nor the hoarseness improved but gait andstance became much more stable and papilloedemaresolved. Blood pressure remained elevated (160/110mmHg) with occasional bouts of hypertensionreaching 200 mmHg systolic. He resumed his previ-ous occupation and when seen in our outpatientdepartment a year later he was found to be well.

DISCUSSION

In their discussion of 10 cases Ignelzi and Bucy(1967) have reviewed comprehensively the clini-cal presentation of the tumour. Most of the caseswere brought to the physician because of symp-toms due to compression of the brain-stem orincreased intracranial pressure rather than thoserelated to the hypoglossal nerve, yet the latterantedated other symptoms from five months upto 10 years, on average 3-1 years. In our casehemiatrophy was noticed eight years before ad-mission. Despite advanced hemiatrophy andfasciculations of the tongue most patients knewof it only after its discovery by the examiningphysician.Vague sensory disturbances, wasting of shoul-

der girdle muscles, hoarseness, and nystagmushave been noted (Scott and Wycis, 1949; Raney,Raney, and Bayless, 1954; McGrew, 1955;Morelli, 1966; Ignelzi and Bucy, 1967). Oftendegenerative neurological disease such assyringobulbia, amyotrophic lateral sclerosis (bul-bar form), and multiple sclerosis were treatederroneously for many years until the diagnosiswas made when signs of increasing intracranialpressure developed (McGrew, 1955). Cerebellarsymptoms, ipsi- and contralateral pyramidaltract dysfunction, and papilloedema resultingfrom obstructive hydrocephalus were seen inmost advanced cases.

Ignelzi and Bucy (1967) stated that benigntumours (neurofibromas and meningiomas) inthe proximity of the foramen magnum showedsurprisingly few radiological changes, in markedcontrast with the mixed group of tumours inthis area.A composite picture of the individual bony

and myelographic findings emerges from the casereports of hypoglossal neurinomas. The presentcase includes all of them.The ideal projections for proper evaluation of

the hypoglossal canal by tomography-routineskull projections being inadequate for the pur-pose-have been worked out by Kirdani (1967)and norms established. Valvassori and Kirdani(1967) presented 14 cases of hypoglossal canalerosion, five of which were due to hypoglossalneurinomas, and emphasized again the indis-pensability of tomography in the appropriateclinical setting. Excavation of the canal from

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within, as the tumour grows within the canal,differentiates neurinoma from extrinsic neoplas-tic (chemodectoma, chordoma, meningioma,lymphoma, and metastasis) and primary bonediseases such as Paget's disease and osteo-myelitis.Myelography and angiography, as in this

case, enable a planned, safe approach to theremoval of the tumour. They also serve to ex-clude risky vascular tumours such as angio-fibroma and chemodectoma which also originatein the intracranial or parapharyngeal region.The high surgical mortality, greater than 60%,

is believed to be due primarily to respiratorydysfunction. In view of this and in order to avoida possible lesion of the lower brain-stem we re-frained from dissecting completely the adherentcapsule and performed immediate tracheostomybefore extubation.The importance of early diagnosis should be

stressed. Hemiatrophy of the tongue seems tohave for this type of tumour a diagnostic import-

ance similar to that attributed to progressivedeafness and impaired caloric vestibular reac-tions for acoustic neuromas.

REFERENCES

Ignelzi, R. J., and Bucy, P. C. (1967). Intracranial hypoglossalneurofibroma. Case report. Journal of Neurosurgery, 26,352-356.

Kirdani, M. A. (1967). The normal hypoglossal canal.American Journal of Roentgenology, Radium Therapy andNuclear Medicine, 99, 700-704.

McGrew, E. A. (1955). Presentation of case. Journal ofAmerican Medical Association, 158, 183-184.

Morelli, R. J. (1966). Intracranial neurilemomma of thehypoglossal nerve. Review and case report. Neurology(Minneapolis), 16, 709-713.

Raney, R. B., Raney, A. A., and Bayless, A. E. (1954).Tumors of hypoglossal nerve; report of case. Bulletin ofLos Angeles Neurological Society, 19, 160-165.

Scott, M., and Wycis, H. T. (1949). Intracranial neurinomaof the hypoglossal nerve. Successful removal, case report.Journal of Neurosurgery, 6, 333-336.

Valvassori, G. E., and Kirdani, M. A. (1967). The abnormalhypoglossal canal. American Journal of Roentgenology,Radium Therapy and Nuclear Medicine, 99, 705-711.

Williams, J. M., and Fox, J. L. (1962). Neurinoma of theintracranial portion of the hypoglossal nerve. Review andcase report. Journal of Neurosurgery, 19, 248-250.

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