Conjunctival Melanocytic Lesions

Can high-resolution optical coherence tomography provide an optical biopsy for ocular surface lesions?

High-resolution optical coherence tomography (HR-OCT) has transformed the diagnosis and management of ocular surface lesions. Providing a detailed cross-sectional view of the cornea and conjunctiva, HR-OCT can be used to identify characteristic features of various benign and malignant ocular surface lesions, aiding in their diagnosis and guiding treatment. When incorporated into an ophthalmology clinic, HR-OCT provides morphological images of lesions in a noninvasive means, akin to an "optical biopsy". The characteristic HR-OCT features of several lesions have been well described in the literature, including for ocular surface squamous neoplasia, papilloma, melanoma, primary acquired melanosis, complexion associated melanosis, nevus, pterygium, pinguecula, lymphoma, and amyloidosis. HR-OCT can be used to differentiate between lesions with similar clinical features, lesions that co-exist on the same ocular surface, and atypically presenting lesions, such as pigmented ocular surface squamous neoplasia or amelanotic melanoma. The management of ocular surface lesions has been transformed by the implementation of HR-OCT, providing clinicians with the ability to monitor tumor response to topical chemotherapies, follow previously excised lesions for recurrence, and map out tumor borders intraoperatively. While there are some limitations to HR-OCT, including imaging of thick or deep lesions, it has become an essential tool for ocular oncologists in the management of ocular surface lesions.

Conjunctival Nevus

Purpose of Review

To provide an up-to-date review of the epidemiology, presentation, diagnosis, and treatment options for conjunctival nevi (CN).

Recent Findings

Around 17.2%-42% of all conjunctival tumors have been found to be CN, which most frequently present in White individuals between the first to early third decade of life, with equal distribution between males and females. CN commonly occur in the interpalpebral bulbar conjunctiva with pigmentation ranging from amelanotic to dark. Diagnosis is typically made through slit lamp examination, visualized by a well circumscribed, variably elevated, variably pigmented, solitary lesion with clear cysts distributed throughout the pigment. In ambiguous cases, anterior segment optical coherence tomography (AS-OCT) can highlight the presence of sub-clinical cysts, whose presence points to a diagnosis of nevus. However, excisional biopsy with histopathology examination is the gold standard for identifying CN.

Summary

CN are benign, variably pigmented lesions. They are the most common of the conjunctival melanocytic tumors. Due to the extremely low risk of transformation to malignant melanoma (MM), CN are usually managed with routine observation and photo documentation.

Unusual conjunctival melanocytic proliferations. Report of five cases and review of the literature

Indeterminate melanocytic proliferations of the conjunctiva have both benign and malignant features that previously made these lesions nearly impossible to categorize in existing classification schemes. With the evolution of immunohistochemistry and molecular genetics, however, subclassifications have emerged that allow for a more tailored diagnosis and management. These conjunctival melanocytic proliferations include deep penetrating nevus, granular cell nevus, and nevoid melanoma. There remains a small subset of conjunctival melanocytic proliferations that defy precise characterization as nevi, primary acquired melanosis, or melanomas despite currently available ancillary diagnostic modalities and remain indeterminate. We highlight these unusual types of nevi and melanomas, with an update on their morphologic, immunohistochemical, and molecular genetic characteristics.

PRAME/MELAN-A double immunostaining as a diagnostic tool for conjunctival melanocytic lesions: A South American experience

INTRODUCTION

PRAME (PReferentially expressed Antigen in Melanoma) is an antigen that is predominantly expressed in human melanomas. In cutaneous melanocytic lesions, PRAME expression is associated with malignancy. The objective of this study was to evaluate the co-expression of PRAME and Melan A to evaluate their diagnostic value in different conjunctival melanocytic lesions (CML).

METHODS

37 CML (23 nevi, 9 primary acquired melanosis (PAM), and 5 conjunctival melanomas) were evaluated by immunohistochemistry for PRAME and Melan-A. The percentage of melanocytic cells co-expressing PRAME and Melan-A was qualitatively evaluated as follows: negative, 0%; 1 + , 1-25%; 2 + , 26-50%; 3 + , 51-75% and 4 + , ≥ 76%.

RESULTS

Of the invasive melanoma cases, 80% showed a 4 + pattern of marking, whereas 20% showed a 3 + pattern. 11% of the PAMs showed a 4 + pattern and 88.9% showed a 1 + pattern. All the nevi showed a 1 + pattern. The sensitivity and specificity of PRAME 4 + for differentiating high-grade CML from the benign and low-grade grouped CML are 93% and 100%, respectively.

CONCLUSION

PRAME/MELAN-A double immunostain is particularly useful to differentiate benign from malignant conjunctival melanocytic lesions.

[Conjunctival tumors in children : Histopathological diagnoses in 262 cases]

BACKGROUND

The spectrum of conjunctival tumors in children and adolescents significantly differs from that of adults.

OBJECTIVE

The aim of this study was to show the distribution of histopathological diagnoses of pediatric conjunctival tumors.

MATERIAL AND METHODS

Retrospective case series including all conjunctival tumors of children and adolescents under 18 years of age examined histologically over a period of 25 years (1990-2015) at the Eye Center in Freiburg, Germany.

RESULTS

Among the 262 conjunctival specimens, the most common diagnoses were conjunctival nevi (148, [56%]), most often with junctional activity (106/148, [72%]), pyogenic granulomas (26, [10%]), and dermolipomas (18, [7%]). In one case a malignant tumor (conjunctival melanoma) was detected (1, < 1%).

CONCLUSION

The results suggest that pediatric conjunctival tumors are benign in most cases. Most of them were of melanocytic origin, with a junctional conjunctival nevus being the most common diagnosis.

Dendritic Melanocytic Hyperplasia in Pterygia: A Potential Source of Diagnostic Confusion with Primary Acquired Melanosis

Introduction

The aim of this study was to report the nearly ubiquitous prevalence of melanocytic hyperplasia in benign pterygia/pingueculae and establish that the entity is insufficiently recognized.

Methods

This is a retrospective immunohistochemical pathology case series of 30 consecutive pterygia/pingueculae samples selected from an ophthalmic pathology database at a single institution. Histopathologic and immunohistochemistry analyses with anti-SOX-10 and anti-MART-1 antibodies were used for identifying melanocytes. The number of squamous cells intervening between melanocytes was determined.

Results

The frequency of dendritic melanocytes was found to meet the criteria for dendritic melanocytic hyperplasia in 29 of 30 pterygia/pingueculae samples using specific antibodies. Melanocytes were found in several patterns: diffuse (28%), multifocal (28%), and focal (44%). In each case, the melanocytes were distributed as single melanocytes at the base; clusters of melanocytes were seen in 17% of samples. There were an average of about two intervening epithelial cells between melanocytes at the base.

Conclusion

When diagnosed with immunohistochemistry, dendritic melanocytic hyperplasia is nearly ubiquitous in pterygia and pingueculae. Melanocytic hyperplasia may have a distribution that includes nests and single melanocytes above the basal layer, which can be confused with forms of primary acquired melanosis. It is important for pathologists to recognize these lesions as a distinct benign clinicopathologic entity.

Bindehautdegenerationen und -neoplasien

Erhabenheiten der Bindehaut entstehen durch Gewebevermehrung, die entweder degenerativ oder neoplastisch, aber auch entzündlich sein können. In diesem Artikel werden degenerative (Pterygium und Pinguecula) sowie benigne und maligne neoplastische Bindehautveränderungen (epitheliale, melanozytäre und vaskuläre Tumoren, Choristome sowie Metastasen) bezüglich der Pathogenese, Symptome, Diagnostik und aktuellem Stand der Behandlung dargestellt.

[Conjunctival Degeneration and Neoplasia]

Conjunctival tumors result from gain of tissue, which can be either degenerative or neoplastic, but also inflammatory. In this article, degenerative (pterygium and pinguecula) as well as benign and malignant neoplastic conjunctival changes (epithelial, melanocytic and vascular tumors, choristomas as well as metastases) are discussed with regard to pathogenesis, symptoms, diagnostics and current status of treatment.