Conjunctival Melanocytic Lesions

Abstract

Context.— Conjunctival melanocytic lesions consist of a variety of neoplastic and nonneoplastic conditions. These include benign processes such as primary intraepithelial hypermelanosis and melanocytic hyperplasia, secondary forms of intraepithelial hypermelanosis and melanocytic hyperplasia, melanocytic nevi, melanocytic proliferations with malignant potential, and melanoma. Objective.— To provide a concise yet comprehensive resource regarding the histopathologic diagnosis of conjunctival melanocytic lesions. We aim to detail and clarify the numerous classification schemes that exist for junctional melanocytic proliferations of the conjunctiva (known as primary acquired melanosis or PAM; also termed conjunctival melanocytic intraepithelial neoplasia or C-MIN). Although not uniformly adopted, C-MIN is classified by using a numeric system based on a defined set of criteria. A less complex scheme (conjunctival melanocytic intraepithelial lesion or CMIL) has recently been proposed by the World Health Organization. Additionally, we aim to update the reader regarding molecular features and prognostic indicators. Data Sources.— Peer-reviewed literature and archived cases for illustration. Conclusions.— Accurate histologic classification is essential, as PAM/C-MIN/CMILs that have a significant potential to progress to invasive melanoma may be clinically indistinguishable from low-risk lesions. Conjunctival melanoma (CM) more closely resembles cutaneous melanoma in terms of its pathogenesis and molecular features, compared to melanoma arising at other mucosal sites or to uveal melanoma. Depth of invasion and ulceration status, among other factors, have emerged as important prognostic indicators in CM. Sentinel lymph node biopsy may provide further prognostic information. Lastly, integration of pathologic and clinical findings is essential at this anatomically sensitive location to determine appropriate clinical management.

PRAME Expression in Junctional Melanocytic Proliferations of the Conjunctiva: A Potential Biomarker for Primary Acquired Melanosis/Conjunctival Melanocytic Intraepithelial Lesions

“…That being said, this distinction has limited practical utility because PAM with high-grade atypia is considered by many authors to be equivalent to conjunctival melanoma in situ. 2 This is reflected in the removal of the category of melanoma in situ from the most recent AJCC Cancer Staging Manual. 19 Similar concordant results were seen in the most recent and largest study by Sekoranja et al In this study, the authors analyzed 188 conjunctival lesions.…”

“…That being said, this distinction has limited practical utility because PAM with high-grade atypia is considered by many authors to be equivalent to conjunctival melanoma in situ. 2 This is reflected in the removal of the category of melanoma in situ from the most recent AJCC Cancer Staging Manual . 19…”

“…1,3,4 Although the clinical term PAM, annotated with the presence or absence of histopathologic atypia by the pathologist, has been most commonly used to refer to these junctional melanocytic proliferations of the conjunctiva, other systems such as the conjunctival melanocytic intraepithelial neoplasia (C-MIN) and conjunctival melanocytic intraepithelial lesion (CMIL) classification schemes have been more recently introduced. 1,2 Other practitioners simply refer to this group of lesions as lentiginous and/or nested junctional melanocytic proliferations and qualify the degree of atypia using a 3-tiered grading system.…”

Bindehautdegenerationen und -neoplasien

“…oder neuerdings cMIL (konjunktivale melanozytäre intraepitheliale Läsion) niedrig- und hochgradig in Bezug auf Malignität 43 , 44 .…”

“…u.) bei wahrscheinlich malignen melanozytären Bindehautveränderungen wünschenswert ist, sind bei einer diffusen Ausbreitung Map-Biopsien (inzisionale Biopsien von verschiedenen Stellen) nötig, um das weitere Prozedere zu bestimmen 44 .…”