British Journal of Neurosurgery (1991) 5 , 83-86


Cavernous angioma of the cerebello-pontine angle: a case report

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The Gough-Cooper Department of Neurological Surgery and Department of Neuropathology, The National Hospital for Nervous Diseases, Queen Square, London WC1N 3NG, UK

Abstract A case of cavernous angioma involving the facial nerve is described. The patient presented with decreased hearing on one side and after investigation a small mass was discovered enlarging the internal auditory meatus. The final diagnosis was made at operation. The pathology of this type of malformation is discussed.

Key words: Cavwnous angioma, arterio-venous malformation, cerebello-pontine angle tumours.



Cavernous angioma is relatively uncommon in the central nervous system and its development in the cerebello-pontine angle with involvement of the facial nerve is exceptional. This malformation may be clinically indistinguishable from other lesions which occur more frequently in this region, such as small intracanalicular acoustic neuromas. We present a patient with a very small cavernous angioma involving the facial nerve, which did not cause any clinically detectable facial weakness.

On examination he had reduced hearing on the left side; his examination was otherwise normal. His past history was unremarkable; he had no headache, cerebellar signs or cranial nerve palsies. Air conduction was greater than bone conduction bilaterally and the Weber test lateralized to the right.

Investigation A pure tone audiogram showed decreased hearing on the left side with loss of 60 dB between 500 and 2000 Hz. C T with and without enhancement, showed that the left internal auditory meatus was wider than the right, but no mass could be seen in this region. Air meatogram showed a mass causing expansion of the left internal meatus, consistent with an acoustic neuroma (Fig. 1). Vertebral angiography showed a hypoplastic left vert2bral

Case report

A 29-year-old school teacher presented with a 3 year history of decreased hearing on the left side; he sought medical advice having noticed difficulty in hearing, most noticeably when using the telephone. He was admitted for investigation. 83


Lorenzo Bordi et al.

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artery, but no definite abnormality could be demonstrated.

underwent surgery 4 days after admission. Through a retromastoid incision a lateral posterior fossa approach was carried out and a porus identified on the posterior face of the petrous bone, with the 7th and 8th cranial nerves. The facial and acoustic nerves were visible going into the PONS, but there was no evident tumour. The porus was then drilled off laterally to expose a mass which lay anterior to the vestibular and cochlear branches of the 8th cranial nerve. It was a small, partly cystic lesion, which almost completely displaced the 7th nerve and was impossible to dissect from it. Removal of the mass could be achieved only by sectioning the facial nerve leaving both branches of the 8th nerve in continuity. A tarsorrhaphy was performed.

Pathology Several fragments received for histopathological examination were fixed in 10% buffered neutral formalin, and routinely processed and embedded in paraffin wax. Sections were stained with haematoxylin and eosin, haematoxylin van Gieson, Luxol Fast Blue, Nissl, and Glees and Marsland silver impregnation for axons. Histological examination showed a cavernous angioma. The tumour consisted of vascular spaces lined by a single layer of flat endothelium in contact with each other or separated by fibrous hyaline tissue (Fig. 2). This contained in places some clusters of inflammatory cells or haemosiderin-laden macrophages. Serial sections of the specimen showed that the angioma was compressing, but not infiltrating a bundle of myelinated peripheral nerve fibres (Fig. 3).

Post-operative course FIG.1. (a) CT scan showing an expanded internal auditory meatus. (b) Air meatogram showing a mass causing expansion of the left acoustic canal.

Operations The probable diagnosis was of a small intracanicular acoustic neuroma. The patient

The patient recovered from anaesthesia with an obvious 7th nerve palsy, and was totally deaf. Two weeks after the first operation, a nerve graft using a piece of the short saphenous nerve was performed through a transmastoidal approach. The graft was attached medially to the proximal stump of the facial nerve in the

Cavernous angioma of the cerebello-pontine angle


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FIG. 2. Photomicrograph showing several enlarged vessels separated by dense and poorly cellular fibrous tissue. Haematoxylin and eosin. X 120.

porus and distally to the nerve in the vertical portion of the facial canal. The patient made an uneventful recovery from his second operation and was discharged from hospital after 10 days. As described in a previous study from this department' the delay in recovery of facial function was recorded and the degree of function assessed according to the scheme proposed by Lye et aL2 Accordingly the patient was seen at follow-up 18 months after discharge from hospital and was found to have good facial movements and good eye closure (Lye Grade 11). He went back to full-time teaching.

Discussion Cavernous angioma is a well-circumscribed lesion, dark red and lobulated which histologically consists of closely packed dilated vascular spaces of various diameters. These are lined by a single layer of endothelium and some of them may be occluded. Areas of calcium deposition are usually found.3 Vascular lesions of the internal auditory canal are rare and only four cases of cavernous angioma have been described involving the 7th n e r ~ e . ~In- ~1976 Sundarensan et al.4 described one such tumour in the intermedius nerve of Wrisberg and another in the facial nerve of two young

FIG. 3. Photomicrograph showing a thin-walled vessel (asterisk) adjacent to a bundle of nerve fibres. Glees and Marsland. X 270.

patients. Dale5 in 1968 reported a cavernous angioma lying just above the facial and vestibular nerves similar to the case described by Schott et aL6 in 1970. Elastic tissue is not usually present in these lesions, but although some authors state that its absence is characteristic.' Others include cases with elastic fibres in their reviews.* Like McCormick,' we think that the vessel component of the tumour is capillary and no elastic fibre should be found in their walls. Dilatation of the abnormal vascular channel

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Lorenzo Bordi et al.

causes enlargement of the mass and despite their non-proliferative, non-neoplastic nature, these lesions may cause progressive signs and symptoms. A small meningioma, because of its vascularity, would probably be shown at angiogra~ h yThe . ~ most likely diagnosis of an avascular mass causing dilatation of the internal auditory meatus in a previously health young man with progressive loss of hearing, is an acoustic neuroma. Both Schott et aL6 and Sunderesan et aL4 reported the presence of marked facial weakness, with or without fasciculation, and a loss of hearing as clinical features in the presence of a small tumour. As in our case, one of Sundaresan et al.’s two cases had a normal vertebral angiogram, while the other showed a slight elevation and medial displacement of the petrosal vein. Dale and Schott did not perform angiographic studies on their patients. The case reported by Dale: like ours, had no facial weakness and therefore, we can only partially agree with Sundaresan et al., who have indicated that loss of hearing and facial weakness, in the presence of a small tumour in the internal acoustic meatus, with or without extension into the cerebello-pontine angle, is the typical clinical picture of a vascular spaceoccupying lesion of the internal acoustic canal.

Address for correspondence and reprints: Prof. L. Symon, Institute of Neurology, The National Hospital, Queen Square, London WClN 3BG, UK. References 1 Sabin HI, Bordi L, Symon L, Compton JS. Faciohypoglossal anastomosis for the treatment of facial palsy after acoustic neuroma resection. Br J Neurosurg 1990; 4:313-8. 2 Lye RH, Dutton J, Ramsden RT, Occleshaw JV, Ferguson IT, Taylor I. Facial nerve preservation during surgery for removal of acoustic nerve turnours. J Neursurg 1982; 57:739-46. 3 Russell DS, Rubinstein LT. Pathology of the Tumours of the Nervous System, 5th edn. London: Edward Arnold, 1989. Sundaresan N, Eller T, Cirie I. Hemangioma of the internal auditory canal. Surg. Neurol 1976; 6:119-21. Dale AJD. The cerebello-pontine angle syndrome. Med Clin North Am 1968; 52(4):789-795. Schott B, Morgan A, Bady B, Bernard A. Cavernome de I’angle ponto-ciribelleux. J Fr Otorhinolaryngol 1970; 19:339-42. McCormick WF. The pathology of vascular “arteriovenous” malformations. J Neurosurg 1966; 24:807-16. Voight K, Yasargil MG. Cavernous angiomas or cavernomas. Neurochirurgia (Stutt), 1976; 19:59-68. Symon L, Kendal BE. Cerebello-pontine angle tumours. In: Shurman K, ed. Advances in Neurosurgery, Vol. 1. New York: Springer-Verlag, 1973.

Cavernous angioma of the cerebello-pontine angle: a case report.

A case of cavernous angioma involving the facial nerve is described. The patient presented with decreased hearing on one side and after investigation ...
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