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Using 18F-fluoro-2-deoxyglucose Positron Emission Tomography to Detect Primary Lung Cancer in an Isolated Choroidal Metastasis
Arch Ophthalmol. 2004;122:1548-1549.
Ocular metastases, and particularly choroidal metastases, can precede detection of primary neoplasm, mainly lung cancers.1 In 39% to 51% of cases, primary tumors remain undetected despite intensive and invasive investigations using conventional tools.1 Based on the increased glycolytic activity, positron emission tomography (PET) scanning is a new imaging method for locating cancer cells used in the localization of primary tumors,2 but it has never been reported in ophthalmology. We report a case of choroidal metastasis from a lung adenocarcinoma only diagnosed by PET scan.
Report of a Case
A 50-year-old man was referred for choroidal metastasis of unknown origin. He had a 1-month history of blurred peripheral vision in the right eye and severe loss of visual acuity. He had smoked 20 cigarettes per day for 35 years. Ophthalmic examination revealed visual acuity worse than 20/400 OD. Anterior segment examination of both eyes and fundus examination of the left eye had normal results. His right fundus showed a solid amelanotic lesion about 5 disc diameters in the posterior pole, including the macula and the optic disc. It was associated with moderate inferior exudative retinal detachments. Ultrasonographic findings of a largest tumor diameter of 14.5 mm and a height of 4 mm and high internal reflectivity associated with fluorescein angiographic findings of hyperfluorescence and numerous pinpoints (Figure 1) were consistent with the diagnosis of choroidal metastasis. Orbital computed tomography scan and magnetic resonance imaging (MRI) (Figure 2) showed a solid mass in the inferior temporal quadrant of the right globe with contrast enhancement. Physical examination results were normal. Neither a primary tumor or additional metastases were found despite extensive investigations including total-body computed tomography, neck ultrasonography, otorhinolaryngeal exploration, bronchoscopy, gastroscopy and colonoscopy, lumbar puncture, cerebral MRI, and bone scintigraphy. A whole-body 18F-fluoro-2-deoxyglucose PET (FDG-PET) scan revealed 2 isolated hypermetabolic foci in the left upper pulmonary lobe and the left hilum, while the eye lesion was not detected (Figure 3 ). The patient received a short course of radiotherapy to the right eye. An upper-left lung lobectomy was performed and confirmed a primary adenocarcinoma (2 cm diameter; T1 N2 M1, stage IV). A chemotherapy of cisplatin and gemcitabine was initiated. At 6 months' follow-up, the choroidal lesion was no longer present and visual acuity has stabilized.
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Figure 1. Fluorescein angiogram (at 1 minute 47 seconds) of the right eye showing hyperfluorescence and numerous pinpoints.
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Figure 2. Axial (A) and sagittal (B) T1-weighted cerebral magnetic resonance imaging showing a solid mass in the temporal quadrant of the right globe (arrows).
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Figure 3. 18F-fluoro-2-deoxyglucose positron emission tomography scan showing 2 isolated hypermetabolic foci in the left upper pulmonary lobe (top arrow) and the left hilum (bottom arrow).
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Comment
Positron emission tomography scanning is able to identify a previously unknown occult primary tumor in 20% to 50% of patients after unsuccessful conventional diagnostic investigations.2 No data are available concerning the smallest size of a lesion that can be detected; detection depends on the lesion's metabolic activity. Furthermore, FDG-PET contributes to detection of tumor dissemination, and to the patient's therapeutic management.3-4 The improvement of primary tumor detection rates is of great prognostic and therapeutic value, especially for patients with 1 solitary visceral metastasis, as an option for curative treatment is not unlikely.3-4 In our particular case, FDG-PET proved to be a very useful method for diagnosis and therapeutic management.
AUTHOR INFORMATION
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Pascal Sève, MD;
Laurent Kodjikian, MD;
Cyrille Vautrin;
Jean-Daniel Grange, MD;
Christiane Broussolle, MD
Correspondence: Dr Sève, Department of Internal Medicine, Hôtel Dieu, 1 place de l'Hôpital, 69288 Lyon Cedex 02, France (pascal.seve{at}chu-lyon.fr).
REFERENCES
1. Small W Jr. Management of ocular metastasis. Cancer Control. 1998;5:326-332.
PUBMED
2. Kole AC, Nieweg OE, Pruim J, et al. Detection of unknown occult primary tumors using positron emission tomography. Cancer. 1998;82:1160-1166.
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3. Lassen U, Daugaard G, Eigtved A, Damgaard K, Friberg L. 18F-FDG whole body positron emission tomography (PET) in patients with unknown primary tumors (UPT). Eur J Cancer. 1999;35:1076-1082.
4. Rades D, Kühnel G, Wildfang I, et al. Localized disease in cancer of unknown primary (CUP): the value of positron emission tomography (PET) for individual therapeutic management. Ann Oncol. 2001;12:1605-1609.
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SECTION EDITOR: W. RICHARD GREEN, MD
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