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Show J. Clin. Neuro-ophthalmol. 4: 103-104, 1984. Postirradiation Optic Neuropathy in Antral Carcinoma JAGMOHAN SINGH, M.D. SUSHMA VASHIST, M.D. Abstract A case is described of a patient who developed radiation-induced optic neuropathy 18 months following cobalt-60 irradiation for carcinoma of the left maxillary antrum and ethmoid sinus. This case is unusual because of the early onset of the optic nerve damage following radiation therapy and the ultimate emergence of the eye involved by tumor compression as the better eye in terms of visual acuity. Radiation-induced optic neuropathy is an uncommon, albeit well-known complication following radiotherapy for intracranial malignancies. I, 2 There are few reports on the development of this condition following radiotherapr. for tumors arising from the paranasal sinuses. -5 A case of carcinoma involving the left maxillary antrum and ethmoid sinus in which radiation-induced optic neuropathy occurred 18 months following cobalt60 irradiation is described. Case Report A50-year-old woman presented with the complaint of persistent epiphora from the left eye for the last 9 years. She previously had a dacryocystorhinostomy for nasolacrimal obstruction which subsequently failed. On examination, the visual acuity was 20/30 in both eyes. Syringing of the nasolacrimal passages revealed a nasolacrimal duct block on the left side. A firm, nontender mass was felt in the inferomedial part of the left orbit adjacent to the From the Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India. June 1984 inferior orbital margin and lacrimal fossa. The posterior limit of this mass could not be determined. Ocular movements were full, and there was no proptosis. Ocular fundus examination revealed mild optic disc swelling in the left eye; the right eye was normal. Roentgenograms of the paranasal sinuses demonstrated a haziness of the left maxillary antrum and ethmoid sinus. A biopsy of the mass revealed the presence a squamous cell carcinoma. Subsequent CT scan showed an extension of the soft tissue mass from the left ethmoid sinus into the left orbit, mainly in the medial and posterior lateral aspect impinging upon the optic nerve. During the diagnostic workup the patient suddenly developed diminution of vision in the left eye to "finger counting at 1 meter: There was an afferent pupillary defect and loss of color discrimination in the left eye. The ocular fundus picture remained unchanged. Cobalt-60 radiotherapy was started, and the patient received 6,500 rads over a period of 7 weeks. Visual acuity at the completion of radiotherapy was 20/30 in the right eye and 20/80 in the left eye. Visual field examination of the left eye revealed marked peripheral constriction. There was telangiectasia of the conjunctival vessels of the left eye. Ocular fundus examination of the left eye demonstrated the continued presence of optic disc swelling with the development of extensive gliosis and dilated, tortuous vessels over and around the disc. Hard exudates were observed in the macular region as well. The right eye was still apparently normal. The patient's visual acuity further improved to 20/60 in the left eye, and there was some regression of the conjunctival and retinal changes. Approximately 18 months following radiotherapy (February 1983), the patient returned with the complaint of progressive, painless diminution of vision in the right eye. Examination of the patient revealed a vision of "light perception with projection." A Marcus Cunn pupil was present in the right eye and temporal pallor of the right optic disc. The left eye had a few telangiectatic conjunctival vessels and resolving optic disc swelling. A repeat CT scan showed the persist- 103 Radiation Optic Neuropathy ence of tumor mass in the left maxillary antrum and ethmoid sinus with extension into the posterior lateral and medial parts of the left orbit. The tumor bulk appeared somewhat smaller. There was no radiologic evidence of extension of the malignancy into the right orbit. Interestingly, ultrasonography done prior to radiologic investigations failed to pick up any mass lesion in the left orbit. Cerebrospinal fluid analysis was performed to rule out carcinomatous optic neuropathy6 and was found to be within normal limits. The clinical picture remained static over the ensuing 5 months of observation. Discussion In patients with paranasal sinus malignancies undergoing radiotherapy, the optic nerves may be sufficiently exposed to doses of radiation high enough to induce vascular effects producing an optic neuropathy. Shukovksy and Fletcher3 describe the various ocular complications following radiotherapy (7,000-7,500 rads) in 30 patients with tumors of the ethmoid sinuses and nasal cavity. They report that optic atrophy due to delayed radiation necrosis developed in three of their cases between 4 and 5 years following radiotherapy. This was characterized by a progressive of vision extending over several months. Optic disc pallor developed within 6 months in these cases. Ross et al. 4 describe a case of epidermoid carcinoma of the maxillary antrum and orbit in which cobalt-60 radiotherapy (6,000 rads) was used as a radiation source. They report their patient developed a radiation-induced optic neuropathy associated with changes in the anterior segment, including cataract, iris atrophy, and rubeosis irides. Brown et al. b describe the ophthalmoscopic findings in a series of 14 patients with radiation-induced optic neuropathy in one eye. They report that eight patients were treated with cobalt-60 plaques for ocular tumors, and six patients were treated with external beam irradiation for a variety of lesions. These patients were followed closely ophthalmoscopically, and in all but one patient the acute phase was heralded by disc edema with surrounding exudates, hemorrhages, and subretinal fluid. Since the patient here was not seen at the time of acute visual loss, it is possible that the visual loss, including disc swelling, was missed. In the series of patients reported by Brown et al.," those treated with cobalt-60 have a mean latency of 12.6 months versus 19.3 months for those treated with external beam irradiation before the development of radiation-induced optic neuropathy. Two of five eyes treated with external beam irradiation (no data available in the sixth case) experienced improvement of vision over a period of 6 months. This is contrasted with patients who develop radiation retinopathy who rarely, if ever, experience visual improvement.6.7 Radiation retinopathy tends to develop earlier than radiation-induced optic neuropathy in patients in whom the focus of therapy is the paranasal sinuses. 3 This pattern is supported by the case reported here. In patients with ocular and orbital disease, the reverse may be true. 6 . 7 Carcinomatous optic neuropathy,8 which was suspected in this case, is not likely as disc edema was not evident in the right eye and cerebrospinal fluid analysis did not reveal any increased protein content or abnormal cells when tested by millipore filter techniques. A striking observation is the ultimate emergence of the left eye (initially compressed by tumor extension) as the better eye in terms of visual acuity. By contrast, the right eye, which was unaffected by the tumor mass, developed optic atrophy as a consequence of radiotherapy. References 1. Zeman, W.: The effects of atomic radiations. In Pathology of the Nen.ous System, Vol. 1, j. Minckler, Ed. McGraw-Hill, London, 1968, pp. 909-912. 2. Miller, N.R.: Walsh alld Hoyt's Clinical Neuro-Ophthalmology (4th ed.). Williams & Wilkins, Baltimore, 1982, pp. 280-282. 3. Shukovsky, L.j., and Fletcher, G.H.: Retinal and optic nerve complications in a high dose irradiation technique of ethmoid sinus and nasal cavity. Radiology 104: 629-634, 1972. 4. Chan, R.c., and Shukovsky, L.j.: Effects of irradiation on the eye. Radiology 120: 673-675, 1976. 5. Ross, H.5., Rosenberg, S., and Friedman, A.H.: Delayed radiation necrosis of the optic nerve. Am. J. Ophthalmol. 76: 683-686, 1973. 6. Brown, G.c., Shields, j.A., Sanborn, G., Augsburger, j.j., Savino, P.j., and Schatz, N.j.: Radiation optic neuropathy. Ophthalmology 89: 1489-1493, 1982. 7. Brown, G.c., Shields, j.A., Sanborn, G., Augsburger, J.j., Savino, P.j., and Schatz, N.J.: Radiation retinopathy. Ophthalmology 89: 1494-1501, 1982. 8. Susac, J.D., Smith, J.L., and Powell, ].0.: Carcinomatous optic neuropathy. Am. f. Ophthalmol. 76: 672-679, 1973. Write for reprillts to: jagmohan Singh, M.D., R/894, New Rajinder Nagar, New Delhi-l10060, India. journal of Clinical Neuro-ophthalmology |
