Difficulties in excluding the diagnosis of retinoblastoma in cases of advanced Coats' disease: a clinicopathologic report

Clinicopathological Correlations in Enucleated Globes of Late-Stage Coats Disease with a Review of the Literature

BACKGROUND

Coats disease may cause diagnostic dilemma because of its variable clinical presentation that can be suspicious of retinoblastoma. Late sequelae of the disease are blinding with possible enucleation. We demonstrate the main histopathological findings of Coats enucleated eyes with literature review.

METHODS

This was a retrospective study of all enucleated globes diagnosed as Coats disease over 30 years and were reviewed by two pathologists. The corresponding demographic data, clinical presentation, pre-operative clinical impression, and indication for enucleation were collected. Descriptive analysis of our own series data was performed. Our findings were then correlated to published data that were collected from 1983 to 2021 from the PUBMED database in English-written language. Shields classification was used as an inclusion criterion for the published reports to be analyzed.

RESULTS

We had seven enucleated globes with Coats disease. Mean age at presentation was 3.2 years (range 3 months to 9 years). Male predominance was observed in 6 and all cases were unilateral. Strabismus was the most common initial presentation (57%, n = 4), followed by leukocoria (43%, n = 3). Indication for enucleation was mostly suspected retinoblastoma (57%, n = 4). Four eyes were classified as stage 4, and 2 had advanced stage 5 changes. Histopathologically, subretinal fluid with lipid-laden macrophages was seen in all cases, the anterior chamber was shallow in 5/7 with angle neovascularization in 2/7. Telangiectatic vessels were clearly observed in 4/7.

CONCLUSION

Coats disease is a potentially visually disabling disease that is mostly unilateral in 95%, has male predominance of 81%, and wide age range with a mean of 17 years. In Saudi Arabia, the disease seems to present at younger age, tends to be more advanced, and may be indistinguishable from retinoblastoma at the time of diagnosis. Shields staging of Coats is highly recommended to be followed clinically to unify the pathways for treatment and to correlate the concluded outcomes.

Coats disease: An overview of classification, management and outcomes

Coats disease is an idiopathic retinal vascular disorder with retinal telangiectasia with intraretinal and/or subretinal exudation without appreciable retinal or vitreal traction. The condition is sporadic with no associated systemic abnormalities. Unilateral involvement in young males is the typical presentation with most cases being diagnosed in the first and second decade of life. Younger the patient, more severe is the presentation and poorer the visual outcome. The management varies with the stage of the disease. Over the years, we have shifted from enucleation to a more conservative approach for the treatment of Coats disease with laser photocoagulation, cryotherapy and surgery for retinal detachment achieving good outcomes. The anti-VEGF agents have come into the scene as important form of adjuvant treatment along with the traditional management options. This article describes the clinical features, underlying pathology, classification and staging, the complications and the management of Coats disease and gives an overview of the changing trends in treatment and outcomes spanning across five decades.

Current management of Coats disease

Since its original description in 1908, Coats disease has been recognized as an idiopathic cause of severe vision loss with a remarkable diversity in clinical presentation and morphology. Key clinical and imaging variables are helpful in differentiating Coats disease from life-threatening malignancies, and proper management revolves around a thorough knowledge of the differential diagnosis. Despite significant advancement in scientific understanding of the disease process and clinical spectrum, the underlying etiology remains obscure, and both primary and secondary forms are recognized. With the development of anti-VEGF therapy, vitreoretinal specialists have a new, effective adjunct to the clinical management of exudates, macular edema, and serous retinal detachment. We highlight the history, diagnostic challenges, evolving clinical spectrum, and current management of Coats disease.

Diagnosis and treatment of coats' disease: a review of the literature

Coats' disease is an idiopathic, ophthalmic condition characterized by retinal telangiectasis, intraretinal and subretinal exudation, which can lead to retinal detachment. It is mostly unilateral, progressive and affects mainly males during childhood, although adult cases have also been described. In this review, we make an update of the literature about Coats' disease, emphasizing on diagnosis and treatment, including the most recent treatment modalities, i.e. anti-vascular endothelial growth factor agents.

[Coats' disease. Important differential diagnosis for retinoblastoma]

Advanced Coats' disease is one of the most difficult differential diagnoses of retinoblastoma in early childhood. We describe the clinical and histological findings in two boys, ages 9 months and 21 months, with unilateral leucocoria. Despite comprehensive diagnostics that included examination under general anaesthesia, magnetic resonance imaging, and ultrasound, retinoblastoma could not be excluded, and the eyes were enucleated. Histological diagnosis of Coats' disease was confirmed. Because differentiation between retinoblastoma and Coats' disease may be difficult, enucleation seems to be indicated in uncertain cases due to the reduced visual prognosis and the risk of secondary complications in advanced Coats' disease.

[Differential diagnosis of retinoblastoma: a retrospective study of 486 cases]

OBJECTIVES

Detail the most frequent problems encountered in the differential diagnosis of retinoblastoma.

PATIENTS

and method: We conducted a retrospective study on the children referred to the Curie Institute for suspicion of retinoblastoma between 2000 and 2006. Diagnosis was made by fundus examination using the indirect ophthalmoscope, ultrasonography, and MRI.

RESULTS

Of the 486 children seen during this period, 408 had unilateral or bilateral retinoblastoma and 78 (16%) had another lesion: Coats disease (20 children, 25%), congenital malformations (23 children, 30%; coloboma, PHPV, microphthalmia, isolated or associated with retinal dysplasia), other tumors (10 children, 13%; astrocytomas and medulloepithelioma), combined hamartomas (six children, 8%), inflammatory diseases (six children, 8%) (Toxocara canis, cat scratch eye disease, or toxoplasmosis), and other diseases (13 children, 16%; corneal opacities, congenital cataract, or retinal detachment).

DISCUSSION

Compared to previous series, this study shows the proportion of erroneous diagnosis has lowered (16%) compared to earlier studies by Balmer (1986; 30%), and Shields (1991; 42%). No cases of retinopathy of prematurity were seen in our series, demonstrating that screening is good or of a lower frequency in France. The frequency of PHPV has dropped. Coats disease remains a frequent and sometimes difficult diagnosis to make, particularly in advanced stages of the disease.

Coats disease: smaller volume of the affected globe

PURPOSE

To determine whether a significant smaller volume of the affected globe, compared with that of the normal globe, is an additional feature of Coats disease.

MATERIALS AND METHODS

Ocular globe volume was assessed in 13 children (11 boys, two girls; age range, 0.6-14 years; mean age, 4.1 years) with Coats disease and in 18 (eight boys, 10 girls; age range, 0.5-12 years; mean age, 3.6 years) with unilateral retinoblastoma. Orbital computed tomographic scans were available for all children; magnetic resonance images were available for 11 children-seven with Coats disease and four with retinoblastoma. For volume estimation, anteroposterior and equatorial diameters of ocular globes were measured. Statistical analysis was conducted with univariate and multivariate methods.

RESULTS

In children with Coats disease, the mean volume of the affected globe was 4,877.03 mm(3) (range, 2,951.47-6,284.70 mm(3)) and that of the normal globe, 6,018.00 mm(3) (range, 4,062.32-7,509.26 mm(3)). In children with retinoblastoma, the mean volume of the affected globe was 4,557.06 mm(3) (range, 1,612.01-7,463.00 mm(3)) and that of the normal globe, 4,402.11 mm(3) (range, 1,360.46- 7,463.00 mm(3)). The Coats disease population had a significantly smaller volume of the affected globe (z = -3.1009; P =.002); the retinoblastoma population did not have a statistically significant trend toward a bigger affected globe volume (z = -1.7064; P =.088). The difference between the affected globe volume and the normal globe volume in children with Coats disease was the only significant independent variable (P =.005).

CONCLUSION

A significantly smaller volume of the affected globe is an additional feature of Coats disease.

Coats' disease and persistent hyperplastic primary vitreous. Role of MR imaging and CT

Coats' disease is an idiopathic disorder in which telangiectatic and aneurysmal retinal vessels leak a lipoproteinaceous exudate, with consequent bullous retinal detachment. It is a diagnostic challenge, and CT and MR imaging provide valuable information to differentiate it from other pathologies, particularly from retinoblastoma. Typical, advanced Coats' disease shows on CT a denser substance posterior to the vitreous, which on MR is hyperintense on all pulse sequences. Contrast administration on both CT and MR might give slight linear enhancement at the boundary between vitreous and exudation. Persistent hyperplastic primary vitreous (PHPV) is a unilateral disorder in a microphthalmic eye, seen in full-term infants. PHPV rarely is bilateral in patients with Norrie's disease, Warburg syndrome, or patients with retinal dysplasia. Persistent fetal vasculature leads to fibrosis, resulting in elongation of the ciliary processes, retinal detachment, and spontaneous cataracts. The CT appearance in the disorder is quite variable; however, MR imaging may be superior in demonstrating the enhancing retrolental mass and the elongated ciliary processes.