|Year : 2022 | Volume
| Issue : 2 | Page : 75-77
Case of a diagnostic challenge: Retinal astrocytic hamartoma or retinoblastoma?
Ankita Kothari, Geoffrey Lam
Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
|Date of Submission||18-Sep-2021|
|Date of Decision||13-Feb-2022|
|Date of Acceptance||21-Feb-2022|
|Date of Web Publication||18-Jul-2022|
Perth Children's Hospital, Nedlands, Western Australia
Source of Support: None, Conflict of Interest: None
Retinal manifestations of tuberous sclerosis (TS) include retinal astrocytomas and retinal granulomas. The retinal astrocytomas and retinal granulomas are benign tumors which clinically appear indistinguishable from retinoblastoma (Rb) lesions in their early stages. We report a case of TS with features of retinal hamartomas which closely resemble Rb lesions. We emphasize the important role of ocular coherence tomography in combination with frequent examinations under anesthesia to differentiate the two entities. TS and Rb can present as the most dangerous combination, and it's best not to assume a malignant condition as a benign one at the cost of a child's life.
Keywords: Retinal astrocytoma, retinoblastoma, tuberous sclerosis
|How to cite this article:|
Kothari A, Lam G. Case of a diagnostic challenge: Retinal astrocytic hamartoma or retinoblastoma?. J Clin Ophthalmol Res 2022;10:75-7
|How to cite this URL:|
Kothari A, Lam G. Case of a diagnostic challenge: Retinal astrocytic hamartoma or retinoblastoma?. J Clin Ophthalmol Res [serial online] 2022 [cited 2022 Aug 19];10:75-7. Available from: https://www.jcor.in/text.asp?2022/10/2/75/351290
Retinal manifestations of tuberous sclerosis (TS) include retinal astrocytomas and retinal granulomas. The retinal astrocytomas and retinal granulomas were seen in TS are benign tumors. Retinoblastoma (Rb) is a rare form of malignant intraocular tumor. It develops from the immature cells of the retina, usually in young children. We present a diagnostic challenging case of multiple intraocular lesions in a case with a family history of TS, but the appearance of the lesions resembles that of Rb.
| Case Report|| |
A 6-month-old baby boy was referred for an ophthalmology workup of TS as he had an episode of a new-onset seizure, with the background of family history of TS.
Magnetic resonance imaging of the brain showed multiple subependymal nodules, cortical/juxtacortical tubers, and radial bands consistent with TS. Fundus examination showed multiple pale, well-defined elevated retinal lesions. There was no evidence of calcifications within the lesions [Figure 1]. Fundus photographs were taken with the RetCam 3® (Natus Medical Incorporated®, California, USA).
|Figure 1: Clinical appearance of retinal astrocytic hamartomas in tuberous sclerosis for the Right eye and Left eye|
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Ocular coherence tomography (OCT) scans were acquired with a portable OCT machine (Bioptigen®, Leica Microsystems®, Wetzlar, Germany). The scans showed the lesions were homogenous and arising from and involving the inner retinal layers [Figure 2]. Given the marked resemblance of the lesions with Rb, it was decided to monitor the child closely with monthly clinic review, intermixed with 3 monthly EUAs for any suspicious changes.
|Figure 2:(a) Ocular coherence tomography image of a retinal astrocytoma lesion appearing homogenous and arising from inner retinal layers, (b) showing the corresponding location through which the OCT image in figure 2 a has been obtained|
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| Discussion|| |
Rb is the most common childhood ocular malignancy. If diagnosed early and managed accordingly, the survival rate is better than 90%. On the other hand, TS is a benign condition. It is important to not misdiagnose a potentially malignant condition as a benign one.
In most cases of TS, the morphological appearance of the retinal lesions is usually diagnostic. Flat translucent retinal hamartomas are the most common lesion found in 70% of patients with TS, followed by the multinodular mulberry lesion which was seen in 55%. With time, these translucent tumors may develop into larger multinodular lesions that have undergone cystic, hyaline, or calcific changes. The lesions can be stationary or may increase in numbers, size, and appearance over time. Although very rare, vitreous seeding has been reported in TS,, making it even more difficult to distinguish between the two.
The typical OCT features of retinal hamartoma in the translucent type of lesions are dome-shaped hyperreflective masses lying within or above the retinal nerve fiber layer, 69.6% limited to the inner retina. The transition from normal retina to tumor is gradual in 77.8% of patients. Similar features have been observed on OCT in our patients [Figure 2]. On the other hand, Shields et al. noted the presence of Rb mass more frequently in the outer retinal layers, elevating the normal-appearing inner retinal layers inward, a feature they termed as “retinal draping.” This feature is apparently more commonly seen in smaller Rb. OCT is also a useful tool to distinguish these features.
Our patient has features consistent with TS. However, Rb needs to be excluded as the morphology of the lesions is difficult to distinguish from Rb [Figure 3]. There are very few reports in the literature to date where Rb has been misdiagnosed as TS based on the presence of systemic features as demonstrated by Zhang et al. and McCaffery et al. In the first report, genetic testing confirmed the diagnosis of Rb, whereas in the second case, there was atypical Rb diagnosed on pathological examination after enucleation. Our patient returned a negative Rb1 gene deletion on genetic testing but showed a mutation in the TSC2 gene which confirms TS. However, a negative Rb1 gene does not exclude the possibility of the presence of Rb. Hence, we followed up this child in accordance with high-risk screening guidelines laid by the American Academy of Ophthalmology (AAO) with monthly examinations for the 1st year and 2 monthly for the following year which we have achieved and thereafter plan future follow-up frequency changes as recommended by AAO. Although the definition of high risk according to the article is on the basis of genetic analysis, we consider our child to be at high risk considering the resemblance of the clinical lesion to Rb.
|Figure 3: Clinical appearance of retinoblastoma lesion in the early stage closely resembling astrocytic hamartoma|
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In another instance, Chawla et al. reported a case in which a clinical diagnosis of Rb was made, and the eye was enucleated. Histopathology of the enucleated eye did not showed malignancy but only features consistent with retinal astrocytoma (TS).
| Conclusion|| |
It can be a diagnostic challenge differentiating retinal astrocytic hamartomas from Rb tumors. OCT proved an essential tool that allows for early detection and differentiation of the two. Nevertheless, as seen in literature, there can be coexistent TS with Rb; hence frequent follow-up visits should continue despite a clinical diagnostic confirmation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]