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Year : 2018  |  Volume : 61  |  Issue : 1  |  Page : 98-100
Coats' disease - disease of the eye rarely encountered by pathologists

1 Department of Pathology, Fr. Muller Medical College, Mangalore, Karnataka, India
2 Department of Radiology, Fr. Muller Medical College, Mangalore, Karnataka, India
3 Department of Ophtholmology, Fr. Muller Medical College, Mangalore, Karnataka, India

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Date of Web Publication22-Mar-2018


Coats' Disease is an idiopathic condition of the eye affecting young children although it can be seen in adults. Most patients present early in life with unilateral decreased vision, strabismus or leukocoria. The most important differential diagnosis is unilateral retinoblastoma. In this study we report a case of coat's disease in an young girl, and evaluate histopathological and clinical findings.

Keywords: Coats' disease, leukocoria, retinal detachment

How to cite this article:
Fernandes H, Umashankar T, Richie AJ, Hegde S. Coats' disease - disease of the eye rarely encountered by pathologists. Indian J Pathol Microbiol 2018;61:98-100

How to cite this URL:
Fernandes H, Umashankar T, Richie AJ, Hegde S. Coats' disease - disease of the eye rarely encountered by pathologists. Indian J Pathol Microbiol [serial online] 2018 [cited 2023 Sep 30];61:98-100. Available from:

   Introduction Top

Coats' disease is a nonhereditary ocular disease, with no systemic manifestation, first described by Coats in 1908.[1] Most patients present early in life with unilateral decreased vision, strabismus, or leukocoria. The most important differential diagnosis is unilateral retinoblastoma, which occurs in the same age group and has some overlapping clinical manifestations. In this study, we report a case of Coats' disease in a young girl and evaluate histopathological and clinical findings.

   Case Report Top

An 18-month-old female baby was brought to eye outpatient department with the complaints of white reflex in the right eye for 1 year, squinting for 6 months, and redness for 2 weeks. On examination, conjunctiva was congested, and cornea was hazy with no visible reflex in the fundus. Intraocular pressure was 53 mmHg, and routine laboratory investigations were all within normal limits. Ultrasonography (USG) showed densely packed internal echoes in ®vitreal cavity with retinal detachment. With these findings possibility of Coats' disease was thought off. Computed tomography scan revealed homogeneous hyperdensity in the posterior segment. A close clinical differential of retinoblastoma had to be ruled out.

Enucleation of the eyeball was carried out. The eyeball was kept for formalin fixation for 2 days. Eyeball measured 2.5 cm anteroposteriorly with attached optic nerve. Cut surface showed pale white triangular band running anteroposteriorly with loss of triangle at the lens, pale yellow granular deposits at the posterior border of vitreous [Figure 1].
Figure 1: Cut section of the eyeball showing a pale white band running anteroposteriorly

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Microscopy showed retinal detachment with amorphous pink material containing cholesterol clefts and foamy macrophages. The detached retina was juxtaposed in the center and was thickened with gliosis along with telangiectatic blood vessels. A diagnosis of Coats' disease was offered [Figure 2].
Figure 2: Microscopy showing retinal detachment with amorphous pink material containing cholesterol clefts and foamy macrophages (H and E, ×10)

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   Discussion Top

Coats' disease is an uncommon disease of childhood although it can be seen even in adults.[2] Patients can present with a range of signs, with the most common being decreased visual acuity, strabismus, and leukocoria. Other signs that can be present in patients with Coats' disease are pain, heterochromia of the iris, and nystagmus. Importantly, although the extent of symptoms is variable, Coats' disease is mainly a progressive condition, which can be asymptomatic in early stages and diagnosed during routine ophthalmologic examination.[3] It is characterized clinically by sheets of subretinal exudation and foci of irregularly dilated capillaries, large microaneurysm, and bizarre configurations of dilated vascular channels.[4] The list of differential diagnosis includes retinoblastoma, persistent hyperplastic primary vitreous (PHPV), and toxocariasis.[5] These can be differentiated on the basis of histopathology.

There are various modalities to confirm the clinical suspicion of Coats' disease. Although it is possible to reach to diagnosis from clinical examination alone, in the majority of cases, some form of ancillary testing such as fluorescein angiography, USG, computerized tomography (CT), and magnetic resonance imaging (MRI) is needed. Fluorescein angiography allows clean visualization of vascular changes. Telangiectasias cause early hyperfluorescence and exudation hyperfluorescence. Aneurysms will be clearly visible, characteristically described as “light bulb dilations.” USG demonstrates subretinal opacities and retinal detachment. Both USG and CT scan can be useful to rule out retinoblastoma because of their ability to pick up calcification. In advanced cases, CT scan shows the lipid exudates as a hyperdense area within the orbit, as well as retinal detachment.[6]

MRI is extremely useful in advanced cases but may have lesser utility during initial stages. Invasive diagnostic modalities such as fine-needle aspiration cytology (FNAC) are not recommended. However, FNAC can be used to confirm the diagnosis when noninvasive modalities are not diagnostic. Shields and Shields at all point out that fine-needle aspiration is contraindicated if there is a total retinal detachment or if there is a strong clinical suspicious of retinoblastoma.[7]

There are two pathological processes which are evident in Coats' disease.[8] The first consists of a breakdown of the blood–retinal barrier at the endothelial level which causes plasma leakage into the vessel wall and thickening of parts of the vessel wall, becoming necrotic and disorganized. Second is the abnormal pericytes and endothelial cells in the retinal blood vessels, which subsequently degenerate, causing aneurysms, as well as the closure of vessels leading to ischemia. This causes leakage of lipid-rich exudates into the retina which can lead to changes in the retina, including thickening, cyst formation, or retinal detachment. The exudate stains positive with periodic acid-Schiff and are rich in lipids and foamy macrophages and cholesterol clefts. These features of Coats' disease help in distinguishing clinical differentials of retinoblastoma, PHPV, and toxocariasis.[9] Retinoblastoma is characterized by the pressure of cells with round nuclei arranged in cuffs that surrounds the retinal vessels. Fleurettes, Flexner–Wintersteiner, and Homer Wright rosettes can be present depending on the degree of differentiation of the tumor. PHPV consists of congenital malformation of the primary vitreous that characterized by a retrolental white plaque of fibrovascular tissue, visible through the pupil. In cases with anterior PHPV, the ciliary processes are drawn inward by their attachment to the fibrotic tissue, while in cases of posterior PHPV, strands of glial tissue extend from the retina into the vitreous. In Toxocara infection, larvae can be found within the chronic granulomatous inflammation.

Natural history of Coats' disease is that of progression to total retinal detachment. Shields et al. proposed the most recent classification system and recommended management as depicted in [Table 1].[9]
Table 1: Classification of Coats' disease

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General pathologists usually do not come across this disease as it is diagnosed in early stages by clinical and radiological examination which helps in saving the globe and also useful vision. Diagnosis of Coats' disease in this patient also was done by clinical and radiological examination. Enucleation was still indicated due to the extensive exudative retinal detachment.

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 initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Coat's G. Forms of retinal disease with massive exudates. R Lond Ophthalmic Hosp Res 1908:17:440-525.  Back to cited text no. 1
Rishi E, Rishi P, Appukuttan B, Uparkar M, Sharma T, Gopal L, et al. Coats' disease of adult-onset in 48 eyes. Indian J Ophthalmol 2016;64:518-23.  Back to cited text no. 2
[PUBMED]  [Full text]  
Haller JA. Coat's disease and Retinal Telangeclasia in Ophthalmology. 2nd ed. In: Myron Y, Duker JS. US: Mosby; 2006.  Back to cited text no. 3
Kremer I, Cohen S, Izhak RB, Ben-Sira I. An unusual case of congenital unilateral Coats's disease associated with morning glory optic disc anomaly. Br J Ophthalmol 1985;69:32-7.  Back to cited text no. 4
Shields CL, Uysal Y, Benevides R, Eagle RC Jr., Malloy B, Shields JA, et al. Retinoblastoma in an eye with features of Coats' disease. J Pediatr Ophthalmol Strabismus 2006;43:313-5.  Back to cited text no. 5
Grant M, Corner, Mark WJ. Coat's Disease and Retinal Telangeetasia in Albert and Jakobiec's Principles and Practices of Ophthalmology. 3rd ed. Philadelphia: Elsevier Inc. 2013.  Back to cited text no. 6
Shields JA, Shields CL. Review: Coat's disease: The 2001 Luesther T. Mertz lecture. Retina 2002;22:80-91.  Back to cited text no. 7
Ghorbanian S, Jaulim A, Chatziralli IP. Diagnosis and treatment of Coats' disease: A review of the literature. Ophthalmologica 2012;227:175-82.  Back to cited text no. 8
Fernandes BE, Odashiro AN, Maloney S, Zajdenweber ME, Lopes AG, Burminer MN Jr: Clinical – Histopathological correlation in a case of Coat's disease. Diagn Pathol 2006;1:24.  Back to cited text no. 9

Correspondence Address:
Hilda Fernandes
Department of Pathology, Fr. Muller Medical College, Mangalore - 575 002, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_826_16

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  [Figure 1], [Figure 2]

  [Table 1]

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