|Year : 2017 | Volume
| Issue : 1 | Page : 27-29
Near-infrared imaging of the choroid in the evaluation of neurofibromatosis
T Lekha, Uddaraju Venkata Sai Shanthi, Jeevamala Mercy Janaki
Department of Ophthalmology, PSGIMSR, Coimbatore, Tamil Nadu, India
|Date of Web Publication||20-Apr-2017|
F5, Marutham Maagnus, V. K. K. Menon Road, New Siddhapudur, Coimbatore, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Near Infrared (NIR) imaging of the fundus with Spectral Domain Optical Coherence Tomography (OCT) with Enhanced Depth Imaging (EDI) is a useful tool to detect choroidal abnormalities in patients with Neurofibromatosis type 1 (NF1). Choroidal neurofibromas were considered rare as it was undetectable by conventional Ophthalmoscopy. NIR imaging utilizes long wavelength Infrared light with good transmission through retinal pigment epithelium providing superior visibility of choroid. We describe 2 female patients aged 20 and 15 years respectively who presented with atypical features of NF1 like unilateral Lisch nodules (first case) and bilateral early Lisch nodules (second case). Fundus examination was normal in both patients. NIR imaging revealed Choroidal neurofibromas as bright patchy lesions with corresponding irregular hyper reflectance on OCT with EDI in both cases, confirming the diagnosis of NF1. This simple, fast and non invasive imaging modality may be recommended in the routine evaluation of patients with NF1.
Keywords: Choroidal neurofibromas, near-infrared imaging, neurofibromatosis
|How to cite this article:|
Lekha T, Shanthi UV, Janaki JM. Near-infrared imaging of the choroid in the evaluation of neurofibromatosis. Egypt Retina J 2017;4:27-9
| Introduction|| |
Neurofibromatosis 1 (NF1) is a complex neurocutaneous disease with clinical variability, age-dependent presentation, and unpredictable evolution, and ophthalmologists are frequently consulted to aid in the diagnosis. The characteristic ocular manifestation is Lisch nodules or iris hamartomas, but as an isolated finding it is not diagnostic. Choroidal neurofibromas were considered rare as they were undetectable with conventional ophthalmoscopy or fluorescein angiography. Near-infrared (NIR) imaging of the fundus is a quick, reliable, and noninvasive method to delineate choroidal neurofibromas and has been recommended as a new diagnostic criterion for NF1. It utilizes long wavelength infrared light (at 815 nm) with good transmission through retinal pigment epithelium providing superior visibility of choroidal pathology.
| Case Report|| |
We present two cases of suspected NF1 where detection of choroidal neurofibromas by NIR imaging helped to confirm the diagnosis. Both patients were females, aged 20 and 15 years, respectively, with no family history of NF1. Thefirst patient had unilateral Lisch nodules [Figure 1] with no systemic features of NF1. The second patient had bilateral early Lisch nodules [Figure 2] with multiple café-au-lait macules. Fundus examination was normal in both patients [Figure 3] and [Figure 4]. NIR imaging of the fundus with confocal scanning laser ophthalmoscopy and spectral domain optical coherence tomography (OCT) with enhanced depth imaging (Spectralis cSLO/OCT with EDI, Heidelberg Engineering, Heidelberg, Germany) revealed two well-defined, bright, rounded choroidal neurofibromas in the left eye in thefirst patient and bilateral multiple choroidal neurofibromas (well-defined rounded type and poorly defined irregular patchy type) in the second patient on the NIR images. The corresponding OCT changes were hyperreflective dome-shaped nodules and irregular placoid formations, respectively [Figure 3] and [Figure 4]. The study was approved by the Institutional Human Ethics Committee of our hospital.
|Figure 1: Anterior segment photograph of the first patient showing normal right eye (a) and two Lisch nodules in the inferior iris in the left eye (b).|
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|Figure 2: (a and b) Anterior segment photograph of the second patient showing multiple small Lisch nodules in both eyes.|
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|Figure 3: (a and b) Normal color fundus photograph of both eyes of the first patient. (c) Normal near-infrared image of the fundus with spectral domain optical coherence tomography of the right eye of the first patient. (d) Near-infrared imaging with spectral domain optical coherence tomography with enhanced depth imaging through the superior choroidal lesion (long white arrow) in the left eye of the first patient. Well-defined, rounded choroidal lesions are seen on the near-infrared image with corresponding hyperreflective dome-shaped choroidal nodule on optical coherence tomography (delineated by the yellow arrows). Compressed choroidal vasculature seen above the nodule. Small white arrow denotes the choroid-scleral junction.|
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|Figure 4: (a and b) Normal color fundus photograph of both eyes of the second patient. (c and d) Near-infrared imaging with spectral domain optical coherence tomography with EDI through the choroidal alterations of the second patient. Multiple well-defined, bright, rounded choroidal lesions and ill-defined, dull, patchy alterations are seen on the near-infrared image bilaterally. Optical coherence tomography section through the well-defined choroidal lesion in the right eye and the ill-defined lesion in the left eye (long white arrow) appears as dome-shaped hyperreflective nodule and irregular hyperreflective placoid formations (delineated by yellow arrows), respectively.|
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| Discussion|| |
Choroidal neurofibromas are ovoid bodies comprising proliferating neoplastic Schwann cells arranged concentrically around axons. They are commonly located at the posterior pole probably due to the greater choroidal thickness and abundant melanocytes and neural cells. They are seen as well-defined, bright, rounded lesions or poorly defined irregular placoid formations with corresponding hyperreflectivity of the choroid on OCT, thus confirming the choroidal localization of these lesions. The reported frequency of choroidal abnormalities in NF1 ranges from 78.9% to 100%, which is higher than the frequency of Lisch nodules. With a cutoff value of 1.5 choroidal nodules, diagnostic accuracy of NIR imaging is 90%. The histological similarity between choroidal neurofibromas and Lisch nodules is in line with the characteristic aberrant proliferation of multiple tissues of neural crest origin in NF1.
Detection of choroidal lesions on NIR imaging helped to confirm the diagnosis of NF1 in our patients who had atypical features such as unilateral Lisch nodules (first case) and early Lisch nodules (second case). Indocyanine green angiography can also demonstrate choroidal pathology, but being an invasive procedure, it has limited use. Magnetic resonance imaging scan of the brain is found to detect lesions of the brain denominated as unidentified bright objects in 70% of patients with NF1 and it is being recommended as a new diagnostic criteria, but it is expensive and requires general anesthesia in children.
| Conclusion|| |
NIR imaging being a reliable, fast, and noninvasive imaging modality may be considered in the routine evaluation of patients with NF1, especially in children and those with atypical presentations, eliminating the need for more costly and invasive investigations.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]