|Year : 2014 | Volume
| Issue : 2 | Page : 104-106
Metastatic orbital adenocarcinoma from an unknown primary site
Francis O Okpala
Department of Radiology, Federal Teaching Hospital Abakaliki, P. M. B. 102, Abakaliki, Ebonyi, Nigeria
|Date of Web Publication||18-Aug-2014|
Dr. Francis O Okpala
Department of Radiology, Federal Teaching Hospital Abakaliki, P. M. B 102, Abakaliki, Ebonyi
Source of Support: None, Conflict of Interest: None
Orbital metastases are rare and are a relatively uncommon cause of adult proptosis. They can be difficult to diagnose, even with new diagnostic imaging techniques. Orbital biopsies with histology can demonstrate about 90% of cases and this diagnosis is often unexpected. In most cases of orbital metastatic disease with an unknown primary site, the site of origin may never be found, even at autopsy. This report is that of an adult male with orbital metastasis that was difficult to diagnose by medical imaging and the primary site could not be found. The rarity of this tumor and the fact that the histological type (adenocarcinoma) is even less common prompted the report of this case.
Keywords: Biopsy, diagnostic imaging, orbital metastasis
|How to cite this article:|
Okpala FO. Metastatic orbital adenocarcinoma from an unknown primary site. J Med Trop 2014;16:104-6
| Introduction|| |
In the Caucasians, orbital metastases are relatively uncommon cause of adult proptotsis; approximately 3-7% of orbital biopsies have demonstrated a metastatic tumor and this diagnosis is often unexpected. ,, Orbital metastases are also rare in Nigeria;  they can be difficult to diagnose,  even with new diagnostic imaging techniques.
A case of metastatic orbital adenocarcinoma in an adult male Nigerian that was difficult to diagnose by medical imaging and which the primary site could not be found is hereby presented. The relative rarity of orbital metastasis and the fact that the primary site proved somewhat elusive prompted the report of this case.
| Case Report|| |
This was a case of a 35-year-old man who presented with 3 months history of right eyeball protrusion and ipsilateral progressive loss of vision. There was no preceding history of trauma. His mother and maternal grandfather died from complications of hypertension.
On physical examination, the right eye showed proptosis, mild ptosis, chemosis, total blindness, partial ophthalmoplegia and an intra-ocular pressure of 21 mmHg (normal value is 10-21 mmHg); fundoscopy revealed intact optic discs. The rest of the physical examination was unremarkable.
His packed cell volume was 54%, erythrocyte sedimentation rate 4 mm/1 st hour, total white blood cell count 9,800 mm 3 (differential count: 75% neutrophils, 20% lymphocytes, 1% eosinophil and 0% basophils and monocytes). The red blood cells and platelets appear normal. Retroviral antibody screening was negative.
Standard chest radiograph showed hypertensive changes of moderate aortic unfolding and mild cardiomegaly. The lung fields were clear and the rib cage was intact. Plain skull X-ray showed hypertrophy of the right inferior turbinate with narrowing of the ipsilateral cavum nasi; the sinuses were clear.
Computed tomogram (CT) of the head showed an enhancing, predominantly extra-conal, infiltrative, soft-tissue mass in the medial wall of the right orbit. The mass extended to, but did not completely cover the orbital apex. It invaded the posterior two-thirds of the medial rectus muscle (which was displaced laterally). The optic nerve was displaced laterally by mass-effect but was connected to the mass at the orbital apex. The right infra-temporal fossa and post-nasal space appeared normal. There was no evidence of bone destruction. The pre- and post-contrast brain scan images were normal [Figure 1] and [Figure 2]. The CT diagnosis was granuloma or pseudo tumor. The differential diagnoses were lymphoma and metastases.
|Figure 1: Contrast enhanced computed tomogram showing that in the medial wall of the right orbit is an enhancing, predominantly extra-conal, infiltrative, soft-tissue mass that extended to, but did not completely cover the orbital apex; the medial rectus muscle is affected|
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|Figure 2: The open arrow points to the R-orbital mass as seen at a level superior to that of Figure 1|
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Orbital and abdominal ultrasonography showed unremarkable findings.
A right exploratory ethmoido-orbitotomy by a combined E.N.T/ophthalmology team showed unusual vascular operating field, orbital contents under pressure and no palpable mass impinging on the optic nerve.
Histology of the excised ethmoidal-orbital specimen showed that the bone was the seat of metastatic epithelial growth, which was mitotically active and that glandular differentiation was focally apparent. The histologic diagnosis of metastatic adenocarcinoma was therefore made.
He had modified exenteration of the right eye, made an uneventful recovery and was discharged 8 days later for follow-up in the out-patient clinic.
| Discussion|| |
Between 2 and 5% of cancer patients will develop orbital metastases , and in 25% of these, it is the presenting sign of malignancy. , Frequently, orbital metastasis presents a diagnostic challenge and with a median survival of 6-9 months, represents a poor prognosis, , as it generally reflect multisystem, end-stage cancer.  The patient in this report did not have a multisystem, end-stage cancer and this is rather contrary to the general belief.
About 12% of orbital metastases are intra-orbital, 86% intra-ocular, especially in the posterior temporal portion of uvea (vascular layer between the retina and sclera) near the macula; it may be bilateral.  Intra-orbital lesions involving the orbital apex are clinically important as they can cause vision loss and ophthalmoplegia.  As shown in the CT exam, the patient had not only an intra-orbital lesion (which is less common than the intra-ocular variety), but also the involvement of the orbital apex. It is therefore not surprising that he had visual loss and ophthalmoplegia.
For tumors metastatic to orbit, the most likely histologic types are large-cell undifferentiated carcinoma and small-cell carcinoma; squamous cell carcinoma and adenocarcinoma have a low incidence.  Open biopsy with histology showed the lesion in our patient to be metastatic adenocarcinoma. The primary site could not be established with the imaging techniques of skull X-ray, chest X-ray, computed tomography of the head and abdominal ultrasonography. Thus, not only did our patient have orbital metastasis (a rare disease), the histological type, adenocarcinoma was also very uncommon.
A metastatic tumor may present with ophthalmic symptoms before the discovery of the primary neoplasm. This is more common with lung, gastrointestinal, thyroid and renal carcinomas. , Although patients with orbital metastatic tumors may present with ptosis, diplopia is the most common presenting symptom, in contrast with primary orbital neoplasms, where either proptosis or visual loss is more common.  This patient being reported presented with proptosis and visual loss. Most commonly the muscle and contiguous orbital structures are involved with metastatic foci; involvement of the muscle alone is less common.  Our patient had muscle and contiguous orbital structure involvement, as well as ptosis.
Though the modalities of choice in the diagnosis of orbital metastases are CT and magnetic resonance (MR), Char et al.  had reported that imaging studies (CT, MR, or both) combined with subjective data may not be diagnostic in some cases. Thus, even with modern imaging tests, there is still a significant false negative diagnostic rate for the detection of this orbital lesion.  Biopsy is still the key for making a confident diagnosis of orbital lesions.  It can be diagnostic in almost 90% of patients with orbital metastases (in sharp contrast to the imaging techniques that have a high false negative rate).  However, in the majority of cases of metastatic disease with an unknown primary site, the site of origin may never be found, even at autopsy.  In the present case, the primary site of origin could not be established.
Since most patients with metastatic orbital disease have a poor prognosis, treatment is usually palliative and may include radiotherapy, chemotherapy, hormone therapy, surgery, or a combination of these.  Surgery (modified exenteration) was the treatment given to this patient. Orbital exenteration is the surgical removal of orbital contents; when any of the contents was spared, the procedure is described as modified exenteration. In this patient, the eyelids were spared for cosmetic purpose.
In the present case, though CT was the most valuable imaging modality used, it was not very specific because metastasis was the least likely of the differential diagnoses made. It is therefore being advocated that biopsy (fine needle aspiration or open biopsy) followed by histology should be done early in the investigation of patients with proptosis, as this can be diagnostic in almost 90% of patients with orbital metastases, in contrast to the non-invasive imaging techniques that have significant false negative diagnostic rate.
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[Figure 1], [Figure 2]