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| CASE REPORT |
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| Year : 1991 | Volume
: 37
| Issue : 2 | Page : 121-2 |
Benign orbital neurilemmoma (a case report).
Asrani SG, Jehangir RP, Adrianwala SD, Sane SY
Department of Ophthalmology, Seth G. S. Medical College, Bombay, Maharashtra.
Correspondence Address:
Department of Ophthalmology, Seth G. S. Medical College, Bombay, Maharashtra.
How to cite this article:
Asrani S G, Jehangir R P, Adrianwala S D, Sane S Y. Benign orbital neurilemmoma (a case report). J Postgrad Med 1991;37:121 |
Benign neurilemmomas have a wide anatomic distribution and may grow along any peripheral or cranial nerve, the auditory nerve being the commonest site - acoustic neuroma. However, it is a rare orbital neoplasm comprising only 1.1% of all orbital tumours [5]. Duke-Elder states that an orbital neurilemmoma is so rare as to be a curiosity[1].
A 19-year-old female presented to the ophthalmic outpatient department with a progressively increasing swelling of the right orbit over a period of 2 years.
She also gave a history of gradual decrease of vision of the right eye and a displacement of the right eye downwards and forwards. There also was a history of some surgery done in the village 1 ½ years ago to remove the swelling, which was unsuccessful. There was no history of pain or similar swellings elsewhere in the body. Examination revealed vision of the right eye to be moving body with good projection of light. There was a singe 5 x 5 cm firm, smooth swelling present in the superior aspect of the orbit which was non-reducible, nonpulsatile and non-tender. It had caused a proptosis of the eye in the downward and axial direction. Elevation and abduction movements of the eye were restricted. A scar of previous surgery was noted on the skin below the eyebrow, which was stretched over the mass with dilated veins (See [Figure - 1]).
The orbital margins were well palpable. The pupil showed a Marcus Gunn reaction to light and the fundus examinations revealed a chronic papilloedema going into optic atrophy. The left eye was completely normal. All the routine blood investigations and chest X-ray were normal. The X-ray of the skull showed an expansile soft tissue mass with no bony changes. The CT scan showed that the mass has confined to the orbital cavity and was not a vascular structure. Systemic examination did not reveal any signs of neurofibromatosis. The patient underwent an excision of the tumour through a skin incision overlying the mass. It was removed entirely with its capsule by dissection from the superior part of the orbit. It measured 6 cm x 4 cm x 4 cm and was bilobed with a constriction at the level of the orbital rim (See [Figure - 2]). A frozen section as well as the final histopathological diagnosis revealed it to be a neurilenimoma with the typical pattern of Antoni A and B cells.
Antoni A, which are elongated cells, are closely packed in interlacing bands or whorled bundles with their oval nuclei arranged in a typical palisade arrangement (like staves on a barrel).
Antoni B cells were open or haphazard fashioned separated by microcystic areas, which may coalesce into large cavernous spaces. Older areas showed haemorrhagic necrosis.
Both type of cells were typically found in different areas of the same tumour. (See [Figure - 3]).
Neurilemmoma is a term introduced by Stout in 1935 for tumours consisting of proliferation of Schwann cells within the sheath of a nerve (quoted by Henderson)[2]. It has also been termed schwannoma by Masson in 1932, perineural fibroblastoma by Penfield in 1927 and neurinoma by Verocay in 1910, (quoted by Rottino and Kelly[4]). It is difficult to distinguish the particular nerve of origin but it is most probably thought to be a branch of the ocutomotor nerve because of its wide ramifications and no sensory symptoms. It usually presents between the ages of 2-70 years, in either sex and in the superior quadrant of the orbit.
Review of the literature reveals very few case reports of benign orbital neurilemmoma[4]. It usually presents as a firm, encapsulated, smooth or nodular, whitish or yellowish grey, solitary mass which is slowly growing with long periods of intermittancy lasting several years (maximum 15 years). The average time between the symptoms and the intervention is 3 years. The size ranges from 2.5 cm x 1.5 cm to 9 x 4 cm. and may show stretched axona on its surface like wisps of a thread. Impaired motility, affection of vision and proptosis are parts of its typical presentation. It is usually delimited within the orbit and meticulous dissection allows only minimal bleeding and no further ocular function damage. However, it may compress the optic nerve. Piecemeal removal runs the risk of malignant transformation as reported in one case in 1971 by Schatz[5]. Thus a neuritemmoma must be kept in mind when dealing with orbital tumours.
We are grateful to the Dean, Seth GS Medical College for allowing us to publish this case report. We are also thinkful Dr Ila M Vora for supplying photographs.
| 1. |
Duke E. System of Ophthalmology. Vol. XIII, Part II. London: Henry Kimpton; 1974, pp 1105-1107.  |
| 2. | Henderson J. Orbital Tumors. Philadelphia: WB Saunders Co; 1973, pp 307-315. |
| 3. | Hogan MJ, Zimmernian LE. Opthalmic Pathology. Ed. 2. Philadelphia: WB Saunders Co; 1962, pp 443-449, 753-757. |
| 4. | Rottino A, Kelly AS. Specific nerve sheath tumors of the orbit and a review of literature. Arch Ophthalmol 1941; 26:478-488. |
| 5. | Schatz H. Benign orbital neurilemmoma-sar. comatous transformation. Arch Orch Ophthalmol 1971; 86:268-273.
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