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    Differentiating Neoplasia From Metaplasia in OSSN

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    Ocular surface squamous neo­plasia (OSSN) is a common ocular ma­lignancy with variable clinical features and a challenging diagnosis. High-res­olution OCT (HR-OCT) can overcome many of the limitations of traditional biopsy for OSSN diagnosis. However, accumulating evidence suggests that HR-OCT has low specificity for differ­entiating dysplasia (e.g., OSSN) from metaplasia, which may lead to unneces­sary treatment of patients with non­neoplastic lesions.

    Researchers from Bascom Palmer in Miami recently compared the HR-OCT findings between OSSN and corneal squamous metaplasia. They found significant overlap in HR-OCT findings and clinical characteristics between OSSN and metaplasia.1

    “Many clinicians use HR-OCT to diagnose ocular cancer and make clin­ical decisions. Our findings, however, show that the inability of HR-OCT to provide information at the cellular level makes this technology incapable of distinguishing OSSN from corneal squamous metaplasia,” said coauthor Anat Galor, MD, MSPH.

    Moreover, she said, the study’s results suggest that “in patients with lesions showing some HR-OCT findings sug-gestive of OSSN, clinicians should also consider squamous metaplasia, espe­cially when patients do not respond to the treatment.”

    She warned that, in some cases, bi­opsy may be needed to confirm or rule out a diagnosis.

    Collecting Clues

    COLLECTING CLUES. Representative (1) slit-lamp photograph and (2) HR-OCT image of an eye with an ocular surface lesion. As neoplastic ocular surface lesions may exhibit characteristics similar to those seen with their nonneoplastic counterparts, combining imaging findings with clinicopathological clues may help clinicians differentiate between different types of lesions.

    Addressing a clinical gap. “We see many patients with ocular surface abnormalities, only some of which are malignant,” said Dr. Galor. HR-OCT findings in OSSN include thickened ep­ithelium, hyperreflectivity, and abrupt transition between normal and abnor­mal epithelium.1 “Anterior segment HR-OCT allows us to observe corneal lesions cross-sectionally and determine whether the lesion is malignant. How­ever, we had instances where a biopsy of lesions with HR-OCT findings suggestive of OSSN showed that the lesions were, in fact, metaplasia,” Dr. Galor said.

    Overlapping HR-OCT findings. For this study, the Bascom Palmer team compared HR-OCT findings between patients with histologically proven cor­neal OSSN and metaplasia (n = 4 per group), and they found that HR-OCT could not differentiate OSSN from metaplasia.

    Dr. Galor suggested that the similar­ities in the histological characteristics of OSSN and metaplasia may contribute to the overlap in HR-OCT findings. “The histological features of both lesion types include epithelial thickening, keratinization, and loss of goblet cells. Because of its resolution, HR-OCT cannot detect mitotic figures and other histological features unique to OSSN.”

    How clinical clues may help. Al­though all lesions were opalescent and localized at the limbus, metaplastic le­sions had smoother and more rounded borders than did OSSN. Additionally, OSSN was more common in fair-skinned individuals, while metaplasia was seen in pigmented individuals. “Combining imaging findings with clinical and demographic clues may better differentiate between the two conditions than imaging alone,” Dr. Galor noted.

    Outlook. “We’re always looking for ways to improve the diagnosis of ocular surface lesions. We are trying to opti­mize the use of HR-OCT to diagnose different types of ocular surface lesions, such as nevi and melanoma, as each of these conditions prompts a differ­ent therapeutic algorithm,” Dr. Galor concluded.

    Overall, she said, patients with OSSN should be treated to prevent tumor progression. In contrast, those with nonneoplastic lesions can receive monitoring alone. Incisional biopsy, the gold standard for OSSN diagnosis, is invasive and may have long turnaround times, leading to potential treatment delays.

    —Christos Evangelou, PhD

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    1 Stevens SM et al. Cornea. 2022. Published online April 9, 2022.

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    Relevant financial disclosures: Dr. Galor—None.

    For full disclosures and the disclosure key, see below.

    Full Financial Disclosures

    Dr. Bellsmith NIH: S; Research to Prevent Blindness: S.

    Dr. Galor AstraZeneca: C; Dompé: C; Eye Cool: C; Novar­tis: C; Ocular Therapeutix: C; Tarsus: C.

    Dr. Scott Allergan: S; NEI: S; Regeneron: C,S.

    Dr. Thomas NIH: S; Research to Prevent Blindness: S.

    Dr. Yam None.

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