Combination of multimodal imaging features predictive of choroidal nevus transformation into melanoma

Advances in multimodal imaging for diagnosis of pigmented ocular fundus lesions

Pigmented ocular fundus lesions can range from benign to malignant. While observation is reasonable for asymptomatic benign lesions, early recognition of tumours that are vision or life threatening is critical for long-term prognosis. With recent advances and increased accessibility of multimodal imaging, it is important that providers understand how to best use these tools to detect tumours that require early referral to subspecialty centres. This review aims to provide an overview of pigmented ocular fundus lesions and their defining characteristics using multimodal imaging. We cover the spectrum of pigmented ocular fundus lesions, including freckle and focal aggregates of normal or near-normal uveal melanocytes, retinal pigment epithelium (RPE) hyperplasia, congenital hypertrophy of the RPE, RPE hamartoma associated with familial adenomatous polyposis, congenital simple hamartoma of the RPE, combined hamartoma of the retina and RPE (congenital hypertrophy of the RPE), choroidal nevus, melanocytosis, melanocytoma, melanoma, adenoma, and RPE adenocarcinoma. We describe key diagnostic features using multimodal imaging modalities of ultra-widefield fundus photography, fundus autofluorescence, optical coherence tomography (OCT), enhanced-depth imaging OCT, ultrasonography, fluorescein angiography, indocyanine green angiography, and OCT angiography (OCTA), with particular attention to diagnostic features that could be missed on fundus examination alone. Finally, we review what is on the horizon, including applications of artificial intelligence. Through skilled application of current and emerging imaging technologies, earlier detection of sight- and life-threatening melanocytic ocular fundus tumours can lead to improved patient prognosis.

Using Deep Learning to Distinguish Highly Malignant Uveal Melanoma from Benign Choroidal Nevi

Background: This study aimed to evaluate the potential of human-machine interaction (HMI) in a deep learning software for discerning the malignancy of choroidal melanocytic lesions based on fundus photographs. Methods: The study enrolled individuals diagnosed with a choroidal melanocytic lesion at a tertiary clinic between 2011 and 2023, resulting in a cohort of 762 eligible cases. A deep learning-based assistant integrated into the software underwent training using a dataset comprising 762 color fundus photographs (CFPs) of choroidal lesions captured by various fundus cameras. The dataset was categorized into benign nevi, untreated choroidal melanomas, and irradiated choroidal melanomas. The reference standard for evaluation was established by retinal specialists using multimodal imaging. Trinary and binary models were trained, and their classification performance was evaluated on a test set consisting of 100 independent images. The discriminative performance of deep learning models was evaluated based on accuracy, recall, and specificity. Results: The final accuracy rates on the independent test set for multi-class and binary (benign vs. malignant) classification were 84.8% and 90.9%, respectively. Recall and specificity ranged from 0.85 to 0.90 and 0.91 to 0.92, respectively. The mean area under the curve (AUC) values were 0.96 and 0.99, respectively. Optimal discriminative performance was observed in binary classification with the incorporation of a single imaging modality, achieving an accuracy of 95.8%. Conclusions: The deep learning models demonstrated commendable performance in distinguishing the malignancy of choroidal lesions. The software exhibits promise for resource-efficient and cost-effective pre-stratification.

Choroidal and Retinal Thicknesses in Healthy Eyes Measured with Ultra-Wide-Field Optical Coherence Tomography

Ultra-wide-field optical coherence tomography (UWF-OCT) has been recently introduced into clinical ophthalmological practice. To date, there are few data on the reference values of the retinal thickness (RT) and choroidal thickness (CT) measured with this technique. This study aimed to analyze the variance in RT and CT in the healthy eyes of white Caucasian patients with UWF-OCT tests performed with the largest available scan size of 23 × 20 mm. The data were analyzed with reference to the patients' age and gender and the axial length of the eyeball. The results of UWF-OCT scanning enabled us to visualize the shape of the retina and choroid in a large portion of the eyeball. Both anatomical entities became significantly thinner at the periphery. The peripheral CT was greater in the upper and temporal sectors; the RT was higher in the nasal compared to the temporal sectors. Both the choroid and retina showed a reduced thickness with age; however, the CT and RT did not show a statistically significant correlation with the axial length after adjusting for age and gender. Age-related variations in thickness were especially prominent in the choroid. The CT in UWF-OCT testing was significantly greater in females, while the RT was greater in males. UWF-OCT testing provides additional information on the anatomical structure of the retina and choroid compared to standard-field OCT.

Multimodal imaging risk factors predictive of small choroidal melanocytic lesion growth to melanoma: An educational study and pictorial guide

BACKGROUND

Risk factors for small choroidal melanocytic lesion growth to melanoma have been redefined using multimodal imaging. We explored provider ability to recognize risk factors for small choroidal melanocytic lesion growth to melanoma before and after image-based education and with and without multimodal imaging.

METHODS

Providers were invited to participate in a survey assessing ability to identify risk factors for small choroidal melanocytic lesion growth to melanoma using either fundus imaging or multimodal imaging. Risk factors included thickness >2 mm on ultrasonography, subretinal fluid on optical coherence tomography, presence of orange pigment by autofluorescence, acoustic hollowness by ultrasonography, and diameter >5 mm by fundus imaging. Performance was assessed before and after reviewing an educational PowerPoint providing pictorial examples of risk factors. Comparison between groups was conducted using two-tailed Fisher's exact test.

RESULTS

Thirty and 26 providers completed the pre-education and post-education assessments, respectively. Post-education participants were more accurate within ±1 risk factor for lesions with zero risk factors (77% vs. 100%, p = 0.01) or two risk factors (79% vs. 91%, p = 0.03). Following education, participants presented with multimodal imaging more often correctly identified lesions with four (12% vs. 42%, p = 0.03) or five (4% vs. 39%, p = 0.004) risk factors, demonstrated lower mean level of concern for lesions with zero risk factors (2.0 vs. 1.4, p < 0.001), and expressed higher level of concern for lesions with 5 risk factors (2.4 vs. 3.6, p < 0.001).

CONCLUSION

Use of multimodal imaging may be more beneficial than education itself to improve accuracy of risk factor identification for small choroidal melanocytic lesions.

Choroidal nevus through a broader vision: Retinal imaging acquisition captured with Broad Line Fundus Imaging technology

OBJECTIVE

To describe the peculiarities in imaging acquisition of fourteen patients with choroidal nevus using the Broad Line Fundus Imaging (BLFI) technology.

METHODS

Single-center, retrospective, cross-sectional analysis.

RESULTS

All images were acquired using the BLFI technology. We have found that choroidal nevus is undetectable in the blue channel (BC) (435-500 nm) and the green channel (GC) (500-585 nm). The only visible changes are related to the drusen, which appeared in BC and GC as light focal dots, correlated to the yellowish foci in the true-color image. On the red channel (RC) (585-640 nm), all lesions revealed the same pattern: a well-defined dark spot, with enhanced contrast, allowing the better visualization, measuring, and characterization of the nevus when compared with the other color channels, including the true-color imaging.

CONCLUSION

BLFI application in choroidal nevus might be helpful at presentation, refining the diagnostic reliability, and monitoring, as it allows for better detection of alterations in the lesions. The peculiarities of the choroidal nevus are better assessed when using the RC due to its longer wavelength and deeper penetration in the retina and choroid.

Quantitative Biomarkers Derived from a Novel, Contrast-Free Ultrasound, High-Definition Microvessel Imaging for Differentiating Choroidal Tumors

Angiogenesis has an essential role in the de novo evolution of choroidal melanoma as well as choroidal nevus transformation into melanoma. Differentiating early-stage melanoma from nevus is of high clinical importance; thus, imaging techniques that provide objective information regarding tumor microvasculature structures could aid accurate early detection. Herein, we investigated the feasibility of quantitative high-definition microvessel imaging (qHDMI) for differentiation of choroidal tumors in humans. This new ultrasound-based technique encompasses a series of morphological filtering and vessel enhancement techniques, enabling the visualization of tumor microvessels as small as 150 microns and extracting vessel morphological features as new tumor biomarkers. Distributional differences between the malignant melanomas and benign nevi were tested on 37 patients with choroidal tumors using a non-parametric Wilcoxon rank-sum test, and statistical significance was declared for biomarkers with p-values < 0.05. The ocular oncology diagnosis was choroidal melanoma (malignant) in 21 and choroidal nevus (benign) in 15 patients. The mean thickness of benign and malignant masses was 1.70 ± 0.40 mm and 3.81 ± 2.63 mm, respectively. Six HDMI biomarkers, including number of vessel segments (p = 0.003), number of branch points (p = 0.003), vessel density (p = 0.03), maximum tortuosity (p = 0.001), microvessel fractal dimension (p = 0.002), and maximum diameter (p = 0.003) exhibited significant distributional differences between the two groups. Contrast-free HDMI provided noninvasive imaging and quantification of microvessels of choroidal tumors. The results of this pilot study indicate the potential use of qHDMI as a complementary tool for characterization of small ocular tumors and early detection of choroidal melanoma.

Understanding choroidal nevus risk factors for transformation into melanoma

A choroidal nevus is a common intraocular tumor in the United States, found in approximately 5% of Caucasian adults. The three main risks of melanocytic choroidal nevus include vision loss from a subfoveal nevus, development of subretinal fluid, and transformation of nevus into melanoma, a malignant counterpart. We explore clinical risk factors that predict benign melanocytic choroidal nevus transformation into a malignant choroidal melanoma. Based on a large analysis of 2,355 cases that were monitored longitudinally using multimodal imaging, the most recent list of clinical features includes tumor Thickness greater than 2 mm on ultrasonography, subretinal Fluid on optical coherence tomography, Symptomatic vision loss 20/50 or worse, Orange pigment on fundus autofluorescence, Melanoma hollow on ultrasonography, and DIaMeter greater than 5 mm on fundus photography. These factors are remembered with a mnemonic of the capital letters TFSOM-DIM for "To Find Small Ocular Melanoma Doing Imaging." Analysis of these factors demonstrated a Kaplan-Meier mean five-year risk of 1% with no risk factors, 11% with any one factor, 22% with any two factors, 34% with any three factors, 51% with any four factors, and 55% with any five factors. There was no patient with six risk factors. Of those with combinations of four risk factors, six of 15 combinations yielded a 70%-100% rate of transformation; of those with combinations of five risk factors, two of five combinations yielded a 70%-100% rate of transformation. Choroidal nevus carries a risk for evolving into melanoma, and understanding of clinical and imaging features predictive of this outcome is highly important.

Predicting Malignant Transformation of Choroidal Nevi Using Machine Learning

Objective

This study aims to assess a machine learning (ML) algorithm using multimodal imaging to accurately identify risk factors for uveal melanoma (UM) and aid in the diagnosis of melanocytic choroidal tumors.

Subjects and Methods

This study included 223 eyes from 221 patients with melanocytic choroidal lesions seen at the eye clinic of the University of Illinois at Chicago between 01/2010 and 07/2022. An ML algorithm was developed and trained on ultra-widefield fundus imaging and B-scan ultrasonography to detect risk factors of malignant transformation of choroidal lesions into UM. The risk factors were verified using all multimodal imaging available from the time of diagnosis. We also explore classification of lesions into UM and choroidal nevi using the ML algorithm.

Results

The ML algorithm assessed features of ultra-widefield fundus imaging and B-scan ultrasonography to determine the presence of the following risk factors for malignant transformation: lesion thickness, subretinal fluid, orange pigment, proximity to optic nerve, ultrasound hollowness, and drusen. The algorithm also provided classification of lesions into UM and choroidal nevi. A total of 115 patients with choroidal nevi and 108 patients with UM were included. The mean lesion thickness for choroidal nevi was 1.6 mm and for UM was 5.9 mm. Eleven ML models were implemented and achieved high accuracy, with an area under the curve of 0.982 for thickness prediction and 0.964 for subretinal fluid prediction. Sensitivity/specificity values ranged from 0.900/0.818 to 1.000/0.727 for different features. The ML algorithm demonstrated high accuracy in identifying risk factors and differentiating lesions based on the analyzed imaging data.

Conclusions

This study provides proof of concept that ML can accurately identify risk factors for malignant transformation in melanocytic choroidal tumors based on a single ultra-widefield fundus image or B-scan ultrasound at the time of initial presentation. By leveraging the efficiency and availability of ML, this study has the potential to provide a non-invasive tool that helps to prevent unnecessary treatment, improve our ability to predict malignant transformation, reduce the risk of metastasis, and potentially save patient lives.

Management of Uveal Melanoma: Updated Cancer Care Alberta Clinical Practice Guideline

OBJECTIVE

The purpose of this guideline update is to reassess and update recommendations in the prior guideline from 2016 on the appropriate management of patients with uveal melanoma.

METHODS

In 2021, a multidisciplinary working group from the Provincial Cutaneous Tumour Team, Cancer Care Alberta, Alberta Health Services was convened to update the guideline. A comprehensive review of new research evidence in PubMed as well as new clinical practice guidelines from prominent oncology groups informed the update. An enhancement in methodology included adding levels of evidence and strength of recommendations. The updated guideline was circulated to all members of the Provincial Cutaneous Tumour Team for review and endorsement.

RESULTS

New and modified recommendations address provider training requirements, diagnostic imaging for the detection of metastases, neo-adjuvant pre-enucleation radiotherapy, intravitreal anti-vascular endothelial growth factor agents for radiation retinopathy, genetic prognostic testing, surveillance following definitive local therapy, and systemic therapy for patients with metastatic uveal melanoma.

DISCUSSION

The recommendations represent evidence-based standards of care agreed to by a large multidisciplinary group of healthcare professionals.

Detection of Circulating Tumor Cells in Patients with Small Choroidal Melanocytic Lesions

PURPOSE

To determine the presence of circulating tumor cells (CTCs) in patients with indeterminate small choroidal melanocytic lesions (SCMLs).

DESIGN

Retrospective case series.

PARTICIPANTS

Forty-seven patients with choroidal melanocytic lesions 2.5 mm or less in tumor thickness and ≤ 10 mm in largest basal diameter (LBD).

METHODS

Blood samples were analyzed for CTCs and the presence of monosomy-3 (M3) in CTCs. Tissue biopsy was performed in the patients who were CTC-positive (pCTC).

MAIN OUTCOME MEASURES

Presence and M3 status of the CTCs with regard to the clinical characteristics and results from tissue biopsy.

RESULTS

Median thickness of all (n = 47) lesions was 1.1 mm (range: 0.2-2.5 mm), and LBD was 5.6 mm (range: 2.0-10.0 mm). Circulating tumor cells were found in 25 patients (n = 25). This group was classified as pCTC and compared with the CTC-negative (nCTC) group consisting of 22 patients (n = 22). Median tumor dimensions in the pCTC versus the nCTC group were 1.6 mm (range: 0.6-2.5 mm) versus 0.5 mm (range: 0.2-2.5 mm) for thickness and 6.6 mm (range: 4.1-10.0 mm) versus 4.0 mm (range: 2.0-8.0 mm) for LBD, respectively. Both LBD and thickness were positively associated (P < 0.001) with the presence of CTC. Compared with the nCTC group, a higher percentage of the pCTC group exhibited LBD > 5 mm (36% vs. 88%), subretinal fluid (9.1% vs. 56%), orange pigment (4.5% vs. 60%), sonographic hollowness (9.1% vs. 60%), and the presence of multiple risk factors (0% vs. 68% for ≥3 factors) with P < 0.001 for all parameters. No significant difference was detected in the clinical parameters of the patients who had disomy-3 (D3) (n = 7) versus M3 (n = 17) in their CTC. The tissue biopsy confirmed the uveal melanoma (UM) in 22 of the 25 pCTC patients (88%), whereas no conclusive diagnosis could be determined in the remaining 3 cases because of insufficient or invalid material.

CONCLUSIONS

We report compelling evidence for the potential of liquid biopsy as an additional tool to screen SCMLs for malignancy. These findings pave the way toward the implementation of liquid biopsy to detect small UM and monitor melanocytic lesions.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Choroidal Nevus Features Associated with Subspecialty Referral

OBJECTIVE

To identify choroidal nevus features associated with referral to a retina or ocular oncology subspecialist.

DESIGN

Population-based retrospective cohort study.

SUBJECTS

Patients diagnosed with choroidal nevus.

METHODS

Population-based retrospective cohort study of residents of Olmsted County, Minnesota, with an incident diagnosis of choroidal nevus from January 1, 2006, to December 31, 2015 using the Rochester Epidemiology Project, a medical record linkage system. Tumor features and patient demographics associated with referral to a retina or ocular oncology subspecialist were assessed. Wilcoxon rank sum test, chi-square test, and Fisher exact test were used for statistical analysis.

MAIN OUTCOME MEASURES

Tumor features and patient demographics associated with referral to subspecialty care.

RESULTS

There were 826 incident diagnoses of choroidal nevus, of which 88 cases (11%) were referred, with highest level of referral being retina in 29 cases (33%) and ocular oncology in 59 cases (67%). None of the analyzed demographic features were associated with choroidal nevus referral to subspecialty care. Tumor features associated with referral (vs. not referred) included greater mean basal diameter (4.6 mm vs. 2.4 mm, P < 0.001), greater mean tumor thickness (0.7 mm vs. 0.1 mm, P < 0.001), greater distance to optic disc (6.9 mm vs. 3.4 mm, P = 0.02), halo around nevus (5.7% vs. 0.4%, P < 0.001), and drusen on OCT (51% vs. 25%, P = 0.002). Presence of orange pigment (8% vs. 0%, P = 0.14), subretinal fluid (9% vs. 2.5%, P = 0.09), and low internal reflectivity on A-scan (7.7% vs. 0%, P = 1.00) were not found more frequently in the subspecialty referral group.

CONCLUSIONS

Greater basal diameter and mean tumor thickness of choroidal nevus were associated with referral to retina or ocular oncology. However, several features associated with increased risk of malignant transformation were not associated with subspecialty referral. These findings highlight the importance of educating eye care providers about high-risk tumor features associated with choroidal nevus transformation to melanoma. In the primary eye care setting where not all multimodal imaging may be available, we encourage color photography and OCT with referral for any features of basal diameter > 5 mm, presence of subretinal fluid, or thickness too large for capture by enhanced-depth imaging OCT.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Optical Density Ratio of Subretinal Fluid in Choroidal Melanomas Versus Choroidal Naevi Assessed by Optical Coherence Tomography

Purpose

The purpose of this study was to determine whether optical density ratio (ODR) of subretinal fluid (SRF) on optical coherence tomography (OCT) differs between choroidal naevi and melanomas.

Methods

One hundred ninety-nine patients (one eye per patient) presenting choroidal melanoma or choroidal naevus with SRF on OCT, evaluated between February and June 2019, were retrospectively included. Other retinal conditions, opaque media, and low-quality OCT were excluded. Mean pixel intensity of SRF (range = 0-255) was quantified using a semi-automated procedure by a masked observer on standard horizontal OCT sections. Mean vitreous intensity served as the reference for ODR.

Results

One hundred twenty-eight patients with choroidal melanoma and 71 patients with choroidal naevus were included in this study. ODR (mean ± SD) was higher in melanomas (181 ± 64) than in naevi (78 ± 48, P < 0.0001). ODR was correlated to lesion thickness (P < 0.0001, r = 0.27), largest basal diameter (P = 0.028, r = 0.16) and, among naevi, to the number of risk factors for growth into melanoma (P = 0.032, r = 0.22). Among 110 patients with naevi or melanoma who underwent fluorescein angiography, ODR was 120.7 ± 550.1 in eyes presenting angiographic pinpoints versus 14.19 ± 26.0 in eyes that did not (P = 0.06). Fourteen eyes with naevi that transformed into melanoma over 3 years had a mean baseline ODR of 94.7 ± 243.5 compared to 4.01 ± 9.74 in 28 matched naevi eyes of similar size that did not transform (P = 0.027).

Conclusions

SRF ODR is higher in choroidal melanoma compared to choroidal naevi. This OCT-derived imaging marker is also higher in choroidal naevi with the potential to transform into melanoma, compared to stationary naevi.

Endoscopic enucleation and clinicopathologic correlation of a small choroidal melanoma hiding massive extrascleral extension

Purpose

To report the unusual case of a previously stable choroidal nevus, closely followed for over 15 years, which underwent malignant transformation into small choroidal melanoma with massive extrascleral extension.

Observations

A 67-year-old Caucasian female was referred to the Stanford Ocular Oncology Service with concern for malignant transformation of a previously stable choroidal nevus in her left eye. Her funduscopic examination demonstrated a dome-shaped choroidal lesion with overlying associated lipofuscin and subretinal fluid, consistent with a diagnosis of small choroidal melanoma. By B-scan ultrasonography, the lesion measured 8.0 × 6.0 mm in base and 2.1 mm in thickness. B-scan ultrasonography also disclosed an associated retroscleral mass, which appeared contiguous with the intraocular melanoma and was confirmed on subsequent orbital magnetic resonance imaging. A decision was made to proceed with enucleation. Under direct endoscopic visualization, the globe and extrascleral mass were fully isolated, mobilized, and removed in toto. At 24 months post-enucleation, the patient remains disease-free without evidence of systemic metastasis or local recurrence.

Conclusions/importance

This case describes a small choroidal melanoma hiding massive extrascleral extension, underscoring the value of B-scan ultrasonography. This case also describes the unique management of choroidal melanoma with extrascleral extension using endoscopic enucleation. Performing enucleation under direct endoscopic visualization ensures complete resection and prevents inadvertent transection of the extrascleral component.

Choroidal Melanoma: A Mini Review

Choroidal melanoma is a rare malignant tumour, yet it is the most common primary intra-ocular neoplasm and second on the list of top ten most malignant melanoma sites in the body. Clinical presentation can be non-specific and includes photopsia, floaters, progressive visual field loss, and blurry vision. The tumour is quite often diagnosed clinically during fundus examination; however, the most valued diagnostic tests are A- and B-scan ultrasonography (US). Several factors affect prognosis, including the patient's age, tumour size, histological features, and presence of metastases. Still, with primary treatment and tight surveillance, around 50% of choroidal melanoma patients metastasise.

[Multimodal algorithm for differential diagnosis of tumors and tumor-like diseases of the ocular fundus]

Diagnosing pathologies of the ocular fundus and performing differential diagnosis of intraocular tumors along with conventional ophthalmoscopy can involve additional visualization methods such as ultrasonography, fluorescein angiography and optical coherence tomography (OCT). Many researchers note the importance of employing a multimodal approach in differential diagnosis of intraocular tumors, but there is no universally established algorithm for a rational choice of both the combination of visualizing methods, and the sequence of their application with consideration of the ophthalmoscopy findings and the results of first-line diagnostic methods. The article presents author's own multimodal algorithm developed for differential diagnosis of tumors and tumor-like diseases of the ocular fundus. This approach involves the use of such methods as OCT and Multicolor fluorescence imaging, with exact sequence and combination determined on the basis of ophthalmoscopy and ultrasonography findings.

Imaging of Uveal Melanoma—Current Standard and Methods in Development

Simple Summary

Uveal melanoma is the most prevalent intraocular tumor in adults, derived from melanocytes; the liver is the most common site of its metastases. Due to troublesome tumor localization, different imaging techniques are utilized in diagnostics, i.e., fundus imaging (FI), ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), or fundus autofluorescence (FAF). Specialists eagerly use these techniques, but sometimes the precision and quality of the obtained images are imperfect, raising diagnostic doubts and prompting the search for new ones. In addition to analyzing the currently utilized methods, this review also introduces experimental techniques that may be adapted to clinical practice in the future. Moreover, we raise the topic and present a perspective for personalized medicine in uveal melanoma treatment.

Abstract

Uveal melanoma is the most common primary intraocular malignancy in adults, characterized by an insidious onset and poor prognosis strongly associated with tumor size and the presence of distant metastases, most commonly in the liver. Contrary to most tumor identification, a biopsy followed by a pathological exam is used only in certain cases. Therefore, an early and noninvasive diagnosis is essential to enhance patients’ chances for early treatment. We reviewed imaging modalities currently used in the diagnostics of uveal melanoma, including fundus imaging, ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), fundus autofluorescence (FAF), as well as positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI). The principle of imaging techniques is briefly explained, along with their role in the diagnostic process and a summary of their advantages and limitations. Further, the experimental data and the advancements in imaging modalities are explained. We describe UM imaging innovations, show their current usage and development, and explain the possibilities of utilizing such modalities to diagnose uveal melanoma in the future.

Fundus Autofluorescence Imaging in Patients with Choroidal Melanoma

Simple Summary

The ocular fundus contains molecules that emit fluorescence when excited with light of an appropriate wavelength. Fundus autofluorescence imaging is based on the in vivo detection of intrinsic fluorescence and results in topographic autofluorescence mapping of the ocular fundus. In contrast to fluorescence angiography, where the fluorescing agents need to be administered intravenously, autofluorescence imaging is a non-invasive technique. Even though choroidal melanomas do not contain significant autofluorescent molecules themselves, they may lead to secondary alterations in neighbouring tissues with an impact on the autofluorescence signal recording. Fundus autofluorescence imaging in the context of choroidal melanoma is helpful for differential diagnosis and for monitoring variations over time in affected patients before and after treatment.

Abstract

Choroidal melanocytic lesions require reliable and precise clinical examination and diagnosis to differentiate benign choroidal nevi from choroidal melanoma, as the latter may become life-threatening through metastatic disease. To come to an accurate diagnosis, as well as for monitoring, and to assess the efficacy of therapy, various imaging modalities may be used, one of which is non-invasive fundus autofluorescence (FAF) imaging using novel high-resolution digital imaging technology. FAF imaging is based on the visualization of intrinsic fluorophores in the ocular fundus. Lipofuscin and melanolipofuscin within the postmitotic retinal pigment epithelium (RPE) cells represent the major fluorophores that contribute to the FAF signal. In addition, the presence or loss of absorbing molecular constituents may have an impact on the FAF signal. A choroidal melanoma can cause secondary retinal and RPE alterations that affect the FAF signal (e.g., occurrence of orange pigment). Therefore, FAF imaging supports multimodal imaging and gives additional information over and above conventional imaging modalities regarding retinal metabolism and RPE health status. This article summarises the features of FAF imaging and the role of FAF imaging in the context of choroidal melanoma, both before and following therapeutic intervention.

Distinguishing Choroidal Nevi from Melanomas Using the MOLES Algorithm: Evaluation in an Ocular Nevus Clinic

OBJECTIVE

The aim of this study was to determine the sensitivity and specificity of the MOLES scoring system in differentiating choroidal melanomas from nevi according to Mushroom shape, Orange pigment, Large tumor size, Enlarging tumor, and Subretinal fluid (SRF).

METHODS

Color photographs, fundus-autofluorescence images, and optical coherence tomography of 222 melanocytic choroidal tumors were reviewed. Each MOLES feature was retrospectively scored between 0 and 2 and tumors categorized as "common nevus," "low-risk nevus," "high-risk nevus," and "probable melanoma" according to the total score. MOLES scores were compared with the experts' diagnosis of melanoma.

RESULTS

The MOLES scoring system indicated melanoma in all 81 tumors diagnosed as such by ocular oncologists (100% sensitivity) and nevus in 135 of 141 tumors given this diagnosis by these experts (95.7% specificity). Of the 6 tumors with discordant diagnoses, 4 had basal diameters exceeding 6 mm, all with SRF and/or orange pigment, and 2 small tumors showed either significant SRF with traces of orange pigment, or vice versa.

CONCLUSIONS

The MOLES system for diagnosing melanocytic choroidal tumors compares well with expert diagnosis but needs to be evaluated when deployed by ophthalmologists and community optometrists in a wide variety of working environments.

Feasibility and Clinical Utility of Ultra-Widefield–Navigated Swept-Source Optical Coherence Tomography Imaging

Purpose:

This work aims to evaluate the clinical utility and feasibility of a novel scanning laser ophthalmoscope-based navigated ultra-widefield swept-source optical coherence tomography (UWF SS-OCT) imaging system.

Methods:

A retrospective, single-center, consecutive case series evaluated patients between September 2019 and October 2020 with UWF SS-OCT (modified Optos P200TxE, Optos PLC) as part of routine retinal care. The logistics of image acquisition, interpretability of images captured, nature of the peripheral abnormality, and clinical utility in management decisions were recorded.

Results:

Eighty-two eyes from 72 patients were included. Patients were aged 59.4 ± 17.1 years (range, 8-87 years). During imaging, 4.4 series of images were obtained in 4.1 minutes, with 86.4% of the image series deemed to be diagnostic of the peripheral pathology on blinded image review. The most common pathologic findings were chorioretinal scars (18 eyes). In 31 (38%) eyes, these images were meaningful in supporting clinical decision-making with definitive findings. Diagnoses imaged included retinal detachment combined with retinoschisis, retinal hole with overlying vitreous traction and subretinal fluid, vitreous inflammation overlying a peripheral scar, Coats disease, and peripheral retinal traction in sickle cell retinopathy.

Conclusions:

Navigated UWF SS-OCT imaging was clinically practical and provided high-quality characterization of peripheral retinal lesions for all eyes. Images directly contributed to management plans, including laser, injection or surgical treatment, for a clinically meaningful set of patients (38%). Future studies are needed to further assess the value of this imaging modality and its role in diagnosing, monitoring, and treating peripheral lesions.

White Paper on Ophthalmic Imaging for Choroidal Nevus Identification and Transformation into Melanoma

Purpose

To discuss the evolution of noninvasive diagnostic methods in the identification of choroidal nevus and determination of risk factors for malignant transformation as well as introduce the novel role that artificial intelligence (AI) can play in the diagnostic process.

Methods

White paper.

Results

Longstanding diagnostic methods to stratify benign choroidal nevus from choroidal melanoma and to further determine the risk for nevus transformation into melanoma have been dependent on recognition of key clinical features by ophthalmic examination. These risk factors have been derived from multiple large cohort research studies over the past several decades and have garnered widespread use throughout the world. More recent publications have applied ocular diagnostic testing (fundus photography, ultrasound examination, autofluorescence, and optical coherence tomography) to identify risk factors for the malignant transformation of choroidal nevus based on multimodal imaging features. The widespread usage of ophthalmic imaging systems to identify and follow choroidal nevus, in conjunction with the characterization of malignant transformation risk factors via diagnostic imaging, presents a novel path to apply AI.

Conclusions

AI applied to existing ophthalmic imaging systems could be used for both identification of choroidal nevus and as a tool to aid in earlier detection of transformation to malignant melanoma.

Translational Relevance

Advances in AI models applied to ophthalmic imaging systems have the potential to improve patient care, because earlier detection and treatment of melanoma has been proven to improve long-term clinical outcomes.

Circulating tumor DNA tracking through driver mutations as a liquid biopsy-based biomarker for uveal melanoma

BACKGROUND

Uveal melanoma (UM) is the most common intraocular tumor in adults. Despite good primary tumor control, up to 50% of patients develop metastasis, which is lethal. UM often presents asymptomatically and is usually diagnosed by clinical examination and imaging, making it one of the few cancer types diagnosed without a biopsy. Hence, alternative diagnostic tools are needed. Circulating tumor DNA (ctDNA) has shown potential as a liquid biopsy target for cancer screening and monitoring. The aim of this study was to evaluate the feasibility and clinical utility of ctDNA detection in UM using specific UM gene mutations.

METHODS

We used the highly sensitive digital droplet PCR (ddPCR) assay to quantify UM driver mutations (GNAQ, GNA11, PLCβ4 and CYSTLR2) in cell-free DNA (cfDNA). cfDNA was analyzed in six well established human UM cell lines with known mutational status. cfDNA was analyzed in the blood and aqueous humor of an UM rabbit model and in the blood of patients. Rabbits were inoculated with human UM cells into the suprachoroidal space, and mutated ctDNA was quantified from longitudinal peripheral blood and aqueous humor draws. Blood clinical specimens were obtained from primary UM patients (n = 14), patients presenting with choroidal nevi (n = 16) and healthy individuals (n = 15).

RESULTS

The in vitro model validated the specificity and accuracy of ddPCR to detect mutated cfDNA from UM cell supernatant. In the rabbit model, plasma and aqueous humor levels of ctDNA correlated with tumor growth. Notably, the detection of ctDNA preceded clinical detection of the intraocular tumor. In human specimens, while we did not detect any trace of ctDNA in healthy controls, we detected ctDNA in all UM patients. We observed that UM patients had significantly higher levels of ctDNA than patients with nevi, with a strong correlation between ctDNA levels and malignancy. Noteworthy, in patients with nevi, the levels of ctDNA highly correlated with the presence of clinical risk factors.

CONCLUSIONS

We report, for the first time, compelling evidence from in vitro assays, and in vivo animal model and clinical specimens for the potential of mutated ctDNA as a biomarker of UM progression. These findings pave the way towards the implementation of a liquid biopsy to detect and monitor UM tumors.

Survival in small choroidal melanocytic lesions with risk factors managed by initial observation until detection of tumour growth

BACKGROUND

The main objective was to describe metastatic and survival rates in patients with small choroidal melanocytic lesions initially managed by observation.

METHODS

Retrospective, observational study of consecutive cases recruited from 2001 through 2018, followed for a median (mean, range) of 81.0 (89.3, 10-204) months in a tertiary referral centre for ocular oncology. Seventy-five consecutive patients diagnosed with small choroidal melanocytic lesions with risk factors for growth initially observed and who showed progression during follow-up. Treatment was performed (plaque radiotherapy or enucleation in 96% and 4% of cases, respectively) at detection of tumour growth.

RESULTS

Median (mean, range) tumour thickness was 2.2 (2.23, 1.08-3.40) mm, and median maximum basal diameter was 8.5 (8.16, 4-12) mm. At diagnosis, a median (mean, range) of 5 (5.48, 1-8) risk factors for progression were present. Lesions grew at a median (mean, range) rate of 0.42 mm/y (1.12, 0-7.68) in thickness and 1.05 mm/y (3.14, 0-4.8) in maximum diameter. Median (mean, range) time until growth was 17.00 (32.6, 1-161) months post-diagnosis, at which time tumours were treated. Five patients developed local recurrence after brachytherapy requiring enucleation. Four patients developed hepatic metastasis. Melanoma-specific survival was 98% at 5 years (95% CI, 94.2-100%) and 91.6% (95% CI, 82-100%) at 10 and 15 years.

CONCLUSION

In small melanocytic lesions with risk factors for growth, initial observation until detection of tumour growth results in a seemingly low risk of metastasis, suggesting that this may be an initial approach to consider in tumours with indeterminate malignant potential.

Application of Multimodal and Molecular Imaging Techniques in the Detection of Choroidal Melanomas

Choroidal melanomas are the most common ocular malignant tumors worldwide. The onset of such tumors is insidious, such that affected patients often have no pain or obvious discomfort during early stages. Notably, enucleation is required for patients with a severe choroidal melanoma, which can seriously impact their quality of life. Moreover, choroidal melanomas metastasize early, often to the liver; this eventually causes affected patients to die of liver failure. Therefore, early diagnosis of choroidal melanomas is extremely important. Unfortunately, an early choroidal melanoma is easily confused with a choroidal nevus, which is the most common benign tumor of the eye and does not often require surgical treatment. This review discusses recent advances in the use of multimodal and molecular imaging to identify choroidal melanomas and choroidal nevi, detect early metastasis, and diagnose patients with choroidal melanomas.

Detecting Progression of Melanocytic Choroidal Tumors by Sequential Imaging: Is Ultrasonography Necessary?

Purpose: To determine if ultrasonography is necessary to detect progression of choroidal melanocytic tumors undergoing sequential multi-modal imaging with color photography, autofluorescence (AF) and optical coherence tomography (OCT). Methods: All patients with choroidal melanoma undergoing treatment at Moorfields Eye Hospital between January 2016 and March 2020 were reviewed to identify those with treatment deferred by ≥2 months. Tumors that showed progression prior to treatment, defined as an increase in (a) basal dimensions (b) thickness (c) orange pigment and/or (d) sub-retinal fluid, were included. Mushroom shape, Orange pigment, Large size, Enlargement and Sub-retinal fluid (MOLES) scores were assigned to all tumors at earliest date and date of treatment. Results: A total of 99 patients with a mean age of 66 years (range: 26-90) were included. The initial MOLES score was 1 in 2 cases, 2 in 23 cases, and ≥3 in 74 cases. Progression was detected with sequential color photography alone in 100% of MOLES 1/2 and 97% of lesions with a MOLES score of ≥3. When findings on AF and OCT were included, sensitivity for detecting subtle change without ultrasonography improved to 100% for MOLES 3 and 97% for MOLES 4/5. Only one patient included in this study had an isolated increase in thickness that may have been missed had sequential ultrasonography not been performed. Overall, the sensitivity for detecting progression with color photographs alone was 97% (95% CI 93-100%) and increased to 99% (95% CI 97-100%) by including autofluorescence and OCT. Conclusions: Monitoring of choroidal nevi, particularly those classified as MOLES 1 or 2 (i.e., low-risk or high-risk naevi), can be accomplished safely without the need for ultrasonography. The findings of this study may remove barriers to the implementation of tele-oncology clinics for the monitoring of choroidal melanocytic tumors.

The MOLES System for Planning Management of Melanocytic Choroidal Tumors: Is It Safe?

PURPOSE

To evaluate the MOLES system for identifying malignancy in melanocytic choroidal tumors in patients treated for choroidal melanoma.

METHODS

Records of 615 patients treated for choroidal melanoma between January 2017 and December 2019 were reviewed. Patients were excluded if iris and/or ciliary body involvement (106 patients), inadequate fundus photography (26 patients), no images available for review (21 patients) and/or treatment was not primary (11 patients). Demographic data and AJCC TNM Stage were collected. Color fundus and autofluorescence photographs (FAF), optical coherence tomography (OCT) and B-scan ultrasounds were prospectively reviewed. MOLES scores were assigned according to five criteria: mushroom shape, orange pigment, large size, enlarging tumor and subretinal fluid.

RESULTS

A total of 451 patients (mean age, 63.9 ± 13.9 years) were included. At treatment, mean largest basal tumor diameter (LBD) and thickness were10.3 ± 2.8 mm (range, 3.0-23.0) and 4.3 mm (range, 1.0-17.0). All but one (0.2%) had MOLES scores of ≥3. Eighty-two patients were treated after surveillance lasting a mean of 1.5 years. Initially, most (63/82; 76.8%) had a MOLES score ≥ 3. Importantly, none of the 451 tumors had a score of <2, and as such, the MOLES protocol would have indicated referral to an ocular oncologist for 100% of patients.

CONCLUSION

The MOLES scoring system is a sensitive (99.8%) tool for indicating malignancy in melanocytic choroidal tumors (MOLES ≥ 3). If the examining practitioner can recognize the five features suggestive of malignancy, MOLES is a safe tool to optimize referral of melanocytic choroidal tumors for specialist care.

[Optical coherence tomography in diagnostics of small choroidal melanoma]

PURPOSE

To determine signs of small choroidal melanoma with different pigmentation using enhanced depth imaging optical coherence tomography (EDI-OCT).

MATERIAL AND METHODS

The study included 344 patients with small choroidal melanoma with different pigmentation examined using EDI-OCT: 1st group - pigmented melanoma (228 eyes), 2nd group - low pigmented (65 eyes), and 3rd group - amelanotic (51 eyes).

RESULTS

In pigmented small choroidal melanomas - elevation of choroidal profile towards vitreous, compression of choriocapillaries with a narrow even 'belt' and a 'shadow' effect; thinning, defects in Bruch's membrane; thickening of the retina above the tumor, lobulated photoreceptors; intra- and subretinal exudate (diffuse, cystic edema, neuroepithelial detachment); defects and detachment of pigment epithelium with hyperreflective foci, disorganization of the pigment with the formation of hyperreflective foci at different retinal levels. In low-pigmented small choroidal melanomas - elevation of choroidal profile towards vitreous, visualized inner surface of the sclera, 'excavation' of the choroid, enlarged choriocapillaries, contour of tumor; thickening of the retina, accumulation of intra- and subretinal exudate (local neuroepithelial detachments); disorganization of the pigment in pigment epithelium with hyperreflective foci in the outer retinal layers. In amelanotic small choroidal melanomas - elevation of choroidal profile towards vitreous, visualized inner surface of the sclera, 'excavation' of the choroid; contouring of choriocapillaries, longitudinal hyperreflective bands in the tumoral stroma, smoothness of the Bruch`s membrane, structural losses of photoreceptors; thickening of the retina (neuroepithelial detachment, diffuse edema); uneven thickening of pigment epithelium.

CONCLUSION

EDI-OCT can help identify microstructural changes in the choroid and adjacent retina in small choroidal melanomas with different degrees of pigmentation, suggesting at the early stages a more aggressive course of the tumoral process affecting the prognosis of the disease. In addition, identification of the microstructure and degree of pigmentation of initial choroidal melanomas is necessary for planning an organ-preserving treatment.

Photoreceptor morphology and correlation with subretinal fluid chronicity associated with choroidal nevus

BACKGROUND

Subretinal fluid (SRF) can be associated with choroidal nevus and can cause progressive change in the morphology of overlying photoreceptors.

METHODS

A retrospective observational study was performed using optical coherence tomography to assess nevus and SRF features, as well as photoreceptor morphology over time.

RESULTS

There were 232 choroidal nevi that presented with or developed SRF. Photoreceptor morphology at presentation was classified as normal (n=60, 26%), shaggy (elongated) (n=73, 31%), retracted (stalactite appearance) (n=76, 33%), or absent (n=23, 10%). There was a progression in photoreceptor morphology with increasing SRF chronicity (p=0.003). For nevus presenting with normal photoreceptors and later developed SRF (n=60), photoreceptors became shaggy in 29 (48%), retracted in 24 (40%), and absent in 7 (12%) after 15, 19 and 22 months, respectively. For nevus presenting with SRF and shaggy photoreceptors (n=73), progression to retracted photoreceptors occurred in 31 (42%) after a mean of 22 months; for nevus with SRF and retracted photoreceptors (n=76), progression to absent photoreceptors occurred in 19 (25%) after a mean of 34 months; and for nevus with absent photoreceptors (n=23), photoreceptor morphology showed no change after mean follow-up of 33 months. Risk of nevus growth to melanoma was not associated with photoreceptor morphology at presentation (p=0.19).

CONCLUSION

In eyes with choroidal nevus and SRF, there is a longitudinal evolution in photoreceptor morphology from normal to shaggy to retracted then absent with increasing SRF chronicity. SRF chronicity, as indicated by photoreceptor morphology on presentation, did not correlate with nevus growth to melanoma.