Anterior high-resolution OCT in the diagnosis and management of corneal squamous hyperplasia mimicking a malignancy: a case report
Anterior high-resolution optical coherence tomography (HR-OCT) is a novel non-invasive in vivo imaging modality that can assist in the diagnosis and management of various ophthalmic pathologies. The implementation of diagnosing ocular surface lesions has been explored in previous studies, successfully revealing specific signs in some ocular lesions. This case report aims to exhibit a case of corneal squamous hyperplasia diagnosed via anterior HR-OCT, prior to surgical intervention.
A 69 year-old male had blurred vision and foreign body sensation OD for several weeks. A rapidly-grown corneal mass was presented, showing an appearance of a grayish flesh-colored mass with elastic texture. Large vessels supplying the mass were also found. Anterior HR-OCT was performed, and the results suggested the lesion be benign hyperplasia. Superficial keratectomy was done, and the pathologic report showed mild-appearing epithelial squamous hyperplasia, which confirmed the analysis via anterior HR-OCT.
In the categorization by Nanji, et al. of corneal surface diseases using anterior OCT, the comparative epithelial thickness (normal range: 47—68 μm); inferior border obscuration of epithelium (normal or benign inferior border: no shadowing); reflectivity of epithelial layer (normal: not hyper-reflective); abrupt transition (normal: no horizontally abrupt transition); and sub-epithelium analysis vary between benign and malignant lesions (normal: demarcated anterior to Bowman’s layer), and the differences are systemically sorted. We applied all these characteristics to our patient as guidance, and the measurement results indicated the lesion be a benign lesion, which is consistent with the tissue pathology. Anterior HR-OCT is overall a non-invasive and timely method capable of assisting the diagnosis of ocular surface disease, predicting the qualities of a lesion, and determining the follow-up treatment plan.
KeywordsAnterior high-resolution optical coherence tomography Corneal squamous hyperplasia
Best-corrected visual acuity
Corneal intraepithelial neoplasia
High-resolution optical coherence tomography
Ocular surface squamous neoplasia
Anterior high-resolution optical coherence tomography (HR-OCT) is a novel non-invasive in vivo imaging modality that can assist in the diagnosis and management of various ophthalmic pathologies [1, 2]. The detection and diagnosis of ocular surface lesions, one of the many implementations of HR-OCT, has been explored in previous studies, successfully revealing optically-diagnostic features with an axial resolution at up to 3 μm . The high resolution granted by HR-OCT not only renders the measurement and analysis of the thickness, reflectivity, and inferior border obscuration of epithelial layers capable, but also visualizes abrupt transitions of epithelial and sub-epithelial layers, allowing for the differentiation of malignancy from normality. This case report aims to exhibit a case with corneal squamous hyperplasia diagnosed with anterior HR-OCT prior to surgical intervention.
Discussion and conclusion
In this case, preoperative anterior HR-OCT, given its ability to visualize anterior-segment non-invasively, was shown useful in the process of delivering a more appropriate surgical treatment plan.
At presentation, the original appearance of the lesion was reminiscent of malignancy due to the gelatinous surface, irregular borders, rapid growth of the mass, and several supplying neo-vessels [4, 5]. The adoption of anterior HR-OCT was called for to further diagnose the patient.
In Nanji, et al.’s analysis via anterior HR-OCT, a normal cornea epithelial layer would be approximately 54.5 μm in thickness (range 47 - 68 μm); in benign lesions such as pterygia, the epithelium would be normal to slightly thickened to around 69 μm (range 37 - 116 μm, under a safe cutoff value of 120 μm); and in malignancies such as ocular surface squamous neoplasia (OSSN) or corneal intraepithelial neoplasia (CIN), epithelial thickness increases to around 390 μm (range 124 - 1000 μm), and the inferior border of a malignant lesion may be partially obscured by shadowing, forming a darkened area under the thickened epithelium. The reflectivity of the epithelial layer of a malignant lesion is strongly hyper-reflective, whereas that of benign lesions such as pterygia or nodular degeneration is either normal or mildly hyper-reflective. In a malignant lesion, an abrupt transition from normal epithelium to a thickened and hyper-reflective epithelium is often observed, while the absence of an abrupt transition usually suggest a benign lesion.
Furthermore, in terms of sub-epithelium analysis, OSSN or CIN usually show no involvement, whereas benign lesions usually show dense, limited, and hyper-reflective fibrillary sub-epithelial lesions located anterior to Bowman’s layer [1, 2, 6]. This feature is compatible with histological findings such as pterygia, in which the fibroblastic lesions are demarcated by Bowman’s layer .
This is a real-world case study of benign hyperplasia evaluated by HR-OCT, and more studies are required to confirm the significance of this method. Cases on other types of malignant lesions, including OSSN or CIN, that are diagnosed with HR-OCT before pathologic proven can be applied for comparison to this case. In addition, to lower the possibility of misdiagnosis due to operational errors during the examination of HR-OCT, pathologic reports are still required for final confirmation.
Making an appropriate treatment plan in cases with atypical ocular lesion is difficult. However, the application of anterior HR-OCT shows efficacy in forming preliminary diagnosis, allowing practicing ophthalmologists to treat patients accurately and timely. Recently, the application of high-resolution OCT has been expanding swiftly and widely in ophthalmologic practices, and real-time imaging was even applied during ocular surgeries . The adoption of such technique may not only improve the diagnostic rate, but also assist in localizing lesions and determining curettage depths. The adoption of OCT angiography in ocular surface lesion to distinguish the flow type of the feeding vessels is also promising, for it may provide more information to differentiate between benign and malignancy in the future .
Despite the suspicion of malignancy given by the clinical impressions in our case, we were able to differentiate the benign hyperplasia from malignancy accurately via anterior HR-OCT prior to operation. The final diagnosis of squamous hyperplasia was further affirmed by the pathology. This case showed the importance of HR-OCT for ophthalmologists by enabling decisions made at earlier stages. With the results at hand, practitioners can make decisions accordingly with different surgical plans and determine whether chemotherapy, such as mitomycin-C, be used during the peri-operative period . Anterior HR-OCT is overall a non-invasive and timely method capable of assisting the diagnosis of ocular surface disease, predicting the qualities of a lesion, and determining the follow-up treatment plan.
YSS and CCH conceived of the presented idea. JLH performed the image analysis and computations. CCH verified the analytical methods. CCH encouraged YSS and JLH to investigate the anterior HR-OCT and CCH supervised the findings of this work. All authors discussed the results and contributed to the final manuscript. All authors have read and approved the manuscript.
Ethics approval and consent to participate
Consent for publication
Written informed consent was obtained from patient for publication of this case report and accompanying images.
The authors declare that they have no competing interests.
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