British Journal of Neurosurgery (1990) 4, 69-72

SHORT REPORT

Schwannoma of the oculomotor nerve

V. S. MEHTA*, R. V. P. SINGH, N. K. MISRA** & CHITRA CHOUDHARYt

*Department of Neurosurgery, **Department of Neuroradiology, Department of Neuropathology, All India Institute of Medical Sciences, New Delhi-I 10029, India

Abstract A case is described of oculomotor nerve sheath turnour presenting with signs and symptoms of a posterior fossa space occupying lesion with minimal involvement of the IIIrd nerve.

Key words: Oculomotor n m e , benign n m e sheath tumour, schwannoma, neurofibroma.

Introduction Benign nerve sheath tumours (neurofibromas or schwannomas) of the nerves innervating the extraocular muscles are extremely rare1v2. T o the best of our knowledge there have been only 23 cases reported so far, of which 14 were of the oculomotor nerve'-18. We describe a case of an oculomotor nerve sheath tumour that presented as a posterior fossa space occupying lesion with minimal IIIrd nerve involvement. None of the cases reported so far had presented as a posterior fossa space occupying lesion.

Case report A 19-year-old female was admitted to the Department of Neurosurgery, All India insti- tute of Medical Sciences, New Delhi, with progressive unsteadiness of gait for 9 months, progressive slurring of speech, and inco-ordi- nation in the right upper limb for 1 month. There was no history of raised intracranial pressure, visual deterioration, diplopia, or hearing impairment. There was no evidence of cafi au lait spots or signs of neurofibromatosis.

Neurological examination revealed bilateral papilledema. Visual acuity in the right eye was 619 and in the left eye 6/12. There was minimal ptosis with slightly larger pupil on the right side. The pupillary reaction to light and accommodation was present. The ocular movements were normal in both eyes. All other cranial nerves were normal. There were marked cerebellar signs which were much more prominent on the right side than the left.

Routine blood biochemistry was within nor- mal limits. Skull radiographs revealed an enlarged sella turcica with the right posterior clinoid destroyed, and the right petrous apex appeared truncated. A contrast enhanced C T scan showed a well-defined uniformly enhanc- ing mass straddling the right petrous apex with a large component in the posterior fossa, and a smaller component in the middle fossa and parasellar region. The upper brainstem was displaced to left and the 4th ventricle could not be identified. The body of the 3rd ventricle was shifted to the left of the midline with moderate dilatation of the lateral and 3rd ventricles (Fig. 1).

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FIG. 1. Contrast enhanced C T scans showing a high density mass straddling the right petrous apex with a large component in the posterior fossa.

A left ventriculoperitoneal shunt was in- serted. Seven days later a right middle tempo- ral trephine craniotomy was carried out and a nearly total excision of a relatively avascular, lobulated, greyish white mass was performed under the microscope. The mass was intradural extracerebral and could be easily separated from the surrounding brain; it was located in the parasellar region and in the inter pendun- cular fossa, extending into the posterior fossa through the tentorial hiatus. The posterior fossa component of the tumour was removed after sectioning the tentorial edge. Most of the tumour was easily aspirated with Cavitron ultra-sonicaspirator. A small portion of the tumour which was thought to be attached to

nerve could not be identified. Postoperatively the patient had a complete

right IIIrd nerve palsy. All other cranial nerves including Vth nerve were normal. The cerebel- lar signs gradually improved and patient was discharged on the 14th postoperative day.

the cavernous sinus was left behind. The IIIrd FIG. 2. Photomicrograph showing spindle shaped tumour cells in a palisaded arrangement. Verrocay bodies are seen. (H&E x 120.)

Histopathological examination showed char- acteristic Antoni Type A and B areas (Fig. 2). In the type A areas the tumour cells were

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Schwannoma of the oculomotor nerve 71

TABLE I.

Case No Author Year

Age/ Duration of sex symp. Symp. signs Remarks

1 .

2.

3. 4. 5. 6. 7.

8.

9.

10.

11.

12.

13.

14. 15.

Kovacs

Shuangshoti

Huber Huber Huber Schubiger et al. Broggi & Franzini

Sako et al.

Hiscott & Symon

Leunda et al.

Kansu er al.

Ischige et al.

Okamato et al.

Nogami et al. Mehta et al.

(Present case)

1927

1975

1978 1978 1978 1980 1981

1981

1982

1982

1982

1985

1985

1986 1988

55/M

64/F

40/F 55/M 52/M 19/F 45/M

29/F

58/F

11/M

15/M

64/F

52/F

40/F 19/F

Incidental- finding at autopsy 6 months

10 years 13 years 6 months 2 years 5 years

8 months

6 months

3 months

-

1 month

1.5 years

6 years 9 months

Seizure, headache, hemiparesis, 11, I11 nerve 11,111 11, 111, VI 111, IV, v, VI 111, IV, v Headache

11, 111 proptosis ICP, dementia hemiparesis, ptosis anisocoria Headache, hemiparesis

Recurrent IIIrd nerve palsy Left retro-orbital pain with ptosis and anisocoria Seizure, proptosis, 111. I11 ICP, cerebellar signs, ptosis. anisocoria

Developed 111 nerve palsy postop.

Developed IIIrd nerve palsy postop.

spindle shaped and arranged in interlacing bundles. Verrocay bodies were identified in the type B areas where the tumour cells were polygonal with vacuolated cytoplasm and ar- ranged in a loose stroma. Hyalinized blood vessels were identified within the tumour. The tumour cells showed mild pleomorphism but no mitosis or necrosis:

Discussion

Intracranial nerve sheath tumours account for about 8% of all intracranial t ~ m o u r ' ~ . Most arise from sensory nerves, and commonly involve the VIIIth nerve, and less frequently the Vth nerve19*20. Involvement of other cranial

nerves and especially the motor nerves is very rare in patients without von-Reckling-hausen's disease4. To the best of our knowledge 23 cases arising from the nerves supplying extraocular muscles have been reported so far; 14 on the oculomotor nerve (Table 1)2,4,6-8,'0-'4,'6-17 7 on the Trochlear nerve1.5,9J1J5J8 and two on the Abducent nerve*,".

Kovak was probably the first to report an isolated oculomotor nerve sheath tumour at autopsy, in 1927'O. Of the 14 cases (Table I) with isolated oculomotor nerve sheath tumour reported so far, 8 were females and 6 were males. The age ranged from 11 years to 64 years with 8 patients above the age of 40 years. The duration of symptoms ranged from 1

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72 V. S. Mehtu et al.

month to 13 years with a mean duration of 36 months. In the present case the duration of illness was of only 9 months. Involvement of IIIrd nerve was noted in all patients preopera- tively with the exception of 2 cases (Case 7 and 10, Table I). Each of these developed persis- tent IIIrd nerve palsy postoperatively. Of the 12 cases where involvement of IIIrd nerve was observed preoperatively two had minimal IIIrd nerve paresis, namely ptosis and anisocoria with full ocular movement. The present case also had mild ptosis and anisocoria with full ocular movement preoperatively . There has been no previously reported case of oculomo- tor nerve sheath tumour presenting with bi- lateral cerebellar signs, which in the present case could have been due to displacement and rotation of the brainstem.

Address for reprints: Dr V . S . Mehta, Depart- ment of Neurosurgery, All India Institute of Medical Sciences, New Delhi-110029, India.

References

Boggen JE, Rosenblum ML, Wilson CB. Neurilem- moma of the fourth cranial nerve. Case report. J Neurosurg 1979; 50519-21. Chen B. Neurinoma of the abducens Nerve. Neurosur- gery 1981; 9:64-6. Broggi G, Franzini A. Value of serial stereotactic biopsies and impedence monitoring in the treatment of brain tumours. J Neurol Neurosurg Psychiatry 1981; 4: 397-401.

4 Hiscott P. Symon L. An unusual presentation of neurofibroma of the oculomotor nerve. Case report. J Neurosurg 1982; 569354-6.

5 Ho KL. Schwannoma of the trochlear nerve, case report. J Neurosurg 1981, 55132-5.

6 Huber A. Das Oculomotoriusneurinom. Klin Monatsbl Augenheilkd. 1978; 172:627-35.

7 Ishcige N, Ito C, Saeki N, Oka N. Neurinoma with intrasellar extension: A case report. No shinkei Geka

8 Kansu T, Ozcan OE, Ozdirim E, Onol B, Gurcay 0. Neurinoma of the oculomotor nerve: case report. J Clin Neuroopthalmol 1982; 2:271-2.

9 King JS. Trochlear nerve sheath tumour. Case report. J Neurosurg 1976; 44:245-7.

10 Kovac W. veber Ein solitares neuronom des nerves oculomotorius. Zentral bl Allg Pathol 1927; 4 0 5 1 8-22.

11 Leunda G, Vaguer0 J, Cabezudo J, Uria JG, Brara G. Schwannoma of the oculomotor nerves, report of four cases. J Neurosurg 1982; 57:563-5.

12 Nogami K, Nishijima M, Endo S , Takaku A. Neuri- noma of the oculomotor nerve: case report. No Shinkei Geka 1986; 14:1237-41.

13 Okamotos, Handa H, Yamashita J. Neurinoma of the oculomotor nerve: Surg Neurol 1985; 24:275-8.

14 Sako K, Abe H, Kaneko S , Tsuru M, Nakano H. Middle fossa neurinoma with proptosis and oculomo- tor palsy, No Shinkei Geka 1981; 9:1153-8.

15 Samii M. Intracranial compression of the third, fourth and sixth cranial nerve by tumours: In: Samii M, Janetta P. Cranial Nerves. ed. Berlin, Heidelberg, New York: Springer-Verlag. 1981, pp. 241-51.

16 Schubiger 0, Valavanis A, Hayek J, Dabir K. Neuronia of the cavernous sinus. Surg Neurol 1980; 13:313-6.

17 Shuangshoti S. Neurilemmoma of the oculomotor nerve Br J Ophthalmol 1975; 59:64-6.

18 Yamamoto M, Jimbo M, Ide M, Kubo 0. Trochlear Neurinoma Surg Neurol 1987; 28:287-90.

19 Schisano G, Olivercrona H. Neurinomas of the gasser- ian ganglian and trigeminal root. J Neurosurg 1960;

20 Russell DS, Rubinstein LJ. Pathology of Tumours of the Nervous System. London: Edward Arnold, 1977: 372.

1985; 13:79-84.

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