A 3-year-old boy presented to Seattle Children’s Hospital after he’d recently emigrated from Vietnam with his mother. Before leaving Vietnam, a doctor told them the boy had a mass in his left eye requiring medical attention. His ocular history was positive for xanthocoria in the left eye first noticed at age 1. At age 2, the patient was noted to have variable eye crossing.
Records from the most recent ophthalmology visit in Vietnam were limited, but stated that the patient had a normal MRI and no additional treatments to the left eye were recommended. His medical history was unremarkable, and family history was negative for any eye diseases or blindness.
What we found on exam
Full Allen chart visual acuity was 20/20 in the right eye and light perception in the left. Intraocular pressures were soft to palpation and symmetric in both eyes. Pupils were equal and symmetrically reactive without afferent pupillary defect. Extraocular motility was full in each eye. The patient showed a variable esotropia of the left eye. The anterior segment exam was unremarkable in each eye.
The dilated fundus exam was unremarkable in the right eye. In the left eye, the dilated fundus exam demonstrated a large, elevated exudative yellowish lesion extending to encompass the majority of the macula, with a distinct gray central elevation. The macula was surrounded by darkly pigmented retina with numerous small exudates extending along the superior and inferior temporal arcades as well as into the periphery 360 degrees (Figure 1).
B-scan in the clinic demonstrated a lesion approximately 2.5 mm in height with high internal reflectivity. It appeared to be either subretinal or choroidal in location (Figure 2). We scheduled an exam under anesthesia (EUA) and obtained hand-held optical coherence tomography, which demonstrated retinal exudation overlying a bilobed subretinal mass in the central macula. Minimal subretinal fluid was associated with the mass.
The choroid directly adjacent to this mass appeared normal without any engorgement leading up to the highly elevated mass. This suggested that the lesion was subretinal rather than choroidal (Figure 3).
Fundus angiography of the left eye using RetCam (Natus Medical) showed early staining in the central macula and in the telangiectatic vessels in the periphery (Figures 4A, B, page 10). Late leakage occurred throughout the periphery, particularly in the area of the telangiectatic vessels temporally. The central macula showed only minimal leakage. Late images showed mostly pooling in the central macula (Figures 4C, D, page 10). The right eye on late frames was normal. We took color photographs of both eyes to document the lesion.
Diagnosis and management
The initial workup in this young boy with xanthocoria and strabismus was most consistent with Coats disease. The differential diagnosis for Coats disease should include retinoblastoma, toxocariasis, familial exudative vitreoretinopathy and retinopathy of prematurity.
The long history of the disease, including the two-year history of xanthocoria, as well as no significant calcification on B-scan, made retinoblastoma unlikely. However, there was some uncertainty about the nature of the central elevated gray mass. Following EUA and fluorescein angiography demonstrating telangiectatic vessels with late leakage throughout the periphery, we felt confident in the presumed diagnosis of Coats disease, and that the central gray area represented subretinal fibrosis.
In a conversation with the family, we outlined treatment options for the disease. These included observation vs. laser treatment vs. anti-VEGF treatment vs. both laser and injections. After talking with the family, we decided to proceed with peripheral laser therapy but not anti-VEGF therapy.
We examined the patient again under anesthesia. We noted abnormal blood vessels in all peripheral quadrants, with the greatest temporally. We used a laser indirect ophthalmoscope, applying 532-nm laser to the abnormal vessels and exudates temporally and to all quadrants with a total of 1,024 spots, a power of 200 mw and a duration of 100 ms.
Features of Coats disease
Coats disease is a congenital condition characterized by unilateral retinal telangiectasia and exudation that predominantly affects young males. It’s named for George Coats, who first described it in 1908.1
Jerry Shields, MD, and colleagues later classified the disease with a system to predict visual prognosis by stratifying patients according to the presence of foveal exudation and exudative retinal detachment on presentation.2 They reported that the absence of foveal exudates at the initial evaluation is cause for a more favorable visual prognosis, while thick foveal exudation usually predicts a worse functional outcome.2
Subfoveal nodules in Coats disease
While we were initially surprised to find a subfoveal nodule in our patient, this has been well described in the literature and noted by both Drs. Shields and Coats in their descriptions of the disease. Coats described coloration indicating subretinal fibrosis, as in this case, having “in parts a grayish reflex, in others a yellowish-white.”1 Dr. Shields and colleagues found that subretinal fibrosis predicted poor visual outcome (final vision < 20/400). However, they didn’t include this in their classification system.2
More recent studies have found subretinal fibrosis present in 23 to 28 percent of patients with Coats.2-6 Alejandro Daruich, MD, and colleagues advocated that this finding should be added to a modified classification system for Coats disease with the addition of subretinal fibrosis to two new subcategories under the original shield classification 2B: 2B1 and 2B2.7
Interestingly, additional studies of subretinal fibrosis in Coats disease found a likely vascular component leading to its development. A study by Sally Ong, MD, and colleagues analyzed OCT, fundus photography, fluorescein angiography and histopathology of eyes with Coats disease.3 This study found intraretinal vessels entering the nodules, leakage on FA and cystoid intraretinal spaces, all of which support the hypothesis that type 3 choroidal neovascular membrane may occur in fibrotic nodules.3,6
While we treated this young patient with laser therapy to the abnormal vessels in the retinal periphery, recent studies have shown that submacular fibrosis likely has a vascular component and anti-VEGF therapy may be warranted.
In deciding on therapeutic options, one should consider the benefits of combined therapy as well as the need for repeated examinations under anesthesia if anti-VEGF therapy is continued. We recommend tailoring treatment based on disease severity. Nevertheless, additional research is needed on the safety and efficacy of these treatment options. RS
1. Coats G. Forms of retinal diseases with massive exudation. R Lond Ophthalmol Hosp Rep. 1908;17:440-525.
2. Shields JA, Shields CL, Honavar SG, et al. Classification and management of Coats disease: The 2000 proctor lecture. Am J Ophthalmol 2001;131:572–583.
3. Ong SS, Cummings TJ, Vajzovic L, Mruthyunjaya P, Toth CA. Comparison of optical coherence tomography with fundus photographs, fluorescein angiography, and histopathologic analysis in assessing Coats disease. JAMA Ophthalmolo. 2019;137:176-183
4. Gupta MP, Dow E, Jeng-Miller KW, et al. Spectral domain optical coherence tomography findings in Coats disease. Retina. 2019;39:1177-1185.
5. Jumper JM, Pomerleau D, McDonald HR, et al. Macular fibrosis in Coats disease. Retina 2010;30:S9–S14.
6. Sigler EJ, Calzada JI. Retinal angiomatous proliferation with chorioretinal anastomosis in childhood Coats disease: A reappraisal of macular fibrosis using multimodal imaging. Retina. 2015;35:537-546.
7. Daruich AL, Moulin AP, Tran HV, et al. Subfoveal nodule in Coats’ disease: Toward an updated classification predicting visual prognosis. Retina 2017;37:1591–1598.