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The clinical, radiological and histopathological findings in an 81-year-old man presenting with lung carcinoma metastatic to the orbit are described. Orbital biopsy was complicated by postoperative visual loss and failed to contribute significantly to the final diagnosis. The authors believe that in cases of possible orbital metastases a primary neoplasm should be excluded by means of a complete oncological assessment before proceeding to biopsy.
Modem treatment modalities resulting in prolonged longevity of cancer patients have led to an increase in the incidence of orbital metastatic disease.1 The presence of a space occupying lesion with unrestricted growth in the bony orbital cavity results in local infiltration and entrapment of structures and cicatrization of soft tissues. Consequently, the symptoms of orbital involvement continue to precede the detection of the primary tumour in 14-42% of cases.2–4 We report a patient with lung carcinoma presenting with monocular blurring of vision. The clinical, radiological and histological features of this case indicate a need to reevaluate our investigative approach in cases of suspected orbital metastases.
An 81-year-old caucasian male presented in October 1995 with a two-week history of mild blurring of vision in the right eye. On questioning he admitted a periorbital ache on the right side. He had a history of hypertension but was otherwise in good health.
On examination visual acuity was 6/12 in the right eye (R.E.) and 6/6 in the left eye (L.E.). The pupils were equal and reacting to light and accommodation and there was no relative afferent pupillary defect. There was full range of eye movements and exophthalmometry was normal and bilaterally symmetrical (14 mm R.E. and L.E.). Anterior segment and fundus findings were unremarkable. Systemic examination was normal. ESR was 4. Follow-up was arranged for 2 weeks later in the outpatient department.
In the intervening period the patient developed horizontal diplopia and more severe right periorbital pain. Visual acuity had deteriorated to 6/36 in the R.E. but pupillary reactions were unchanged. A 4 mm non-axial proptosis was noted on exophthalmometry and there was significant limitation of abduction, adduction and depression of the right eye. A CT scan revealed an intraconal mass adjacent to the medial rectus in the right orbit. The sinuses were not involved. (Fig. 1)
Coronal MRI scan confirmed the presence of an intraorbital mass displacing the optic nerve laterally and superiorly. (Fig. 2) An open orbital biopsy was undertaken under general anaesthesia. Infiltration of the biopsy tissue with poorly differentiated carcinoma was seen on microscopy. The patient suffered a postoperative reduction of vision to vague perception of light in spite of orbital decompression and several pulses of high-dose intravenous methylprednisolone.
Formal oncological investigations were then performed. Left hilar shadowing characteristic of lung carcinoma was seen on chest x-ray, in contrast with the preoperative chest X-ray which showed only a possible small cystic lesion in the left mid-zone. Liver involvement was confirmed on ultrasound and widespread bony metastases were seen on the radionucleotide scan.
This case raises several issues which need to be addressed. First, a clinical presentation of visual disturbance alone is unusual in cases of orbital metastatic disease. Previous investigators have found proptosis, motility disturbance, mass and ptosis to be the most common presenting signs of secondary deposits in the orbit. However, these signs are preceded by a reduction of vision in about 3% of cases.5,6 The possibility of a space occupying lesion within the orbit should be considered in all cases of unexplained monocular visual disturbance.
The radiological features of this case also require discussion. There is much debate as to whether a CT scan or MRI is the investigation of choice in cases of suspected orbital masses. Although MRI results in a greater range of contrast in tissues and superior anatomic detail, it offers no distinct advantage over a CT scan in depicting orbital lesions.7 The CT scan visualises bony detail and soft tissues8 and it delineates well the orbital compartments because of the large amount of fat within the cavity.9 However, the neuroradiologist should be furnished with clear instructions regarding the necessity of films in the coronal plane and the use of contrast. In the case reported here these instructions were omitted and therefore only an axial CT scan was performed. Consequently, MRI was required in order to obtain a cross-sectional evaluation of the orbit. The decision as to which imaging modality to use to evaluate orbital pathology is also based on other considerations including cost, availability and the physical limitations of the patient.
This case also illustrates that orbital biopsy is not a risk-free procedure. The two most serious complications of orbital biopsy include optic nerve compression and retrobulbar haemorrhage. We believe our patient suffered a dramatic drop in visual acuity because of postoperative oedema resulting from surgical manipulation of a lesion in such close proximity to the optic nerve.
Tijl et al. found that 79% of patients with orbital metastatic disease had evidence of secondary deposits at other sites, most frequently bone.5 It may therefore be appropriate to carry out a more thorough oncological evaluation, including radioisotope bone scan, before considering orbital biopsy. This would obviate the need for many patients to undergo a potentially sight-threatening procedure in a condition where maintenance of quality of life is the aim of management.
In conclusion, although the long-term prognosis for these patients remains poor, it is imperative that we arrive at a prompt and accurate diagnosis for two reasons. First, preservation of vision and a higher quality of life are associated with earlier commencement of palliative treatment. 10 Second, a shorter delay in establishing the diagnosis will provide patients with more time to arrange their family and personal affairs.
We wish to thank the staff of the department of pathology at Queens Medical Centre, Nottingham for their advice and assistance with this report.