Retinoblastoma presenting as Coats’ disease

Sir,

We present a case of atypical presentation of retinoblastoma masquerading as Coats’ disease.

Case report

A healthy 4-year-old boy presented with leukocoria of the right eye. On examination, the patient demonstrated poor visual fixation in the right eye and steady fixation in his left eye. During examination under anaesthesia, intraocular pressures were within normal ranges. Ultrasonography confirmed a detached and diffusely thickened retina with no intraretinal calcification. Indirect ophthalmoscopy revealed an unusual exudative retinal detachment. The retina was diffusely thickened and associated with intraretinal and preretinal haemorrhages, a white flocculent material in between areas of retinal folds, and an anomalous retinal vasculature pattern throughout (Figure 1a). Intraoperative fluorescein angiography confirmed this unusual vascular pattern with arterio-venous communication, prominent telangiectatic vessels, leakage, and 360° of peripheral capillary non-perfusion (Figure 1b and d). Anterior segment evaluation showed diffuse iris hyperfluorescence consistent with iris neovascularization (Figure 1c).

Figure 1

Indirect funduscopy photographs show (a) exudative retinal detachment with white flocculent material, retinal folds, anomalous vasculature, and haemorrhage. (b) Peripheral retinal vasculature with arterio-venous communication. (c) Fluorescein angiogram of the anterior segment shows prominent iris neovascularization and (d) FA of the posterior segment shows telangiectasia, leakage, and peripheral capillary non-perfusion.

The differential diagnosis included Coats’ disease, persistent hyperplastic primary vitreous, retinal dysplasia, and an atypical presentation of retinoblastoma. Given the uncertainty over the clinical diagnosis and the poor visual prognosis, enucleation of the eye was performed. Pathologic study revealed an endophytic mass arising from the retina extending from ora to ora, with vitreous seeding and extensive exudate in the subretinal space. There were large basophilic nuclei with mitotic figures (Figure 2). The diagnosis of retinoblastoma with Coat-like response was confirmed.

Figure 2

Macrophotograph of haemotoxylin and eosin-stained section of the enucleated eye. The retina is replaced by an intraretinal mass extending from ora to ora, with extensive subretinal exudate.

Comment

Atypical manifestations of retinoblastoma (presenting at older age, with unusual features such as pseudohypopyon, hyphaema, or vitreous haemorrhage) can pose diagnosis challenges. Retinoblastoma masquerading as Coats’ disease has been described previously.¹ This case is unique because ultrasonography and fluorescein angiography strongly mimicked typical findings in Coats’ disease, including lack of calcification, dilated telangiectatic vessels with leakage, and peripheral non-perfusion. Shields and Shields² have suggested that the calibre and distribution of retinal blood vessels can help distinguish Coats’ from retinoblastoma. In this case, fluorescein angiography was misleading. It is important for ophthalmologists to maintain a high index of suspicion for retinoblastoma in all children with unusual ocular diseases in which the diagnosis is not clear.