Table 5.

2022 World Health Organization Classification of Conjunctival Melanocytic Intraepithelial Lesions [2]

WHO	Acceptable alternative terminology	Increased cellularity	Histologic features	Risk of association with or progression to invasive melanoma
Not applicable	Benign melanosis c-MIN (grades (0–1) PAM without atypia	No/minimal	Conjunctival hypermelanosis (increased pigment in epithelial cells without melanocytic hyperplasia or atypia). Slight or focal melanocytic hyperplasia without atypia (parabasal melanocytes with condensed round nuclei, smaller than basal epithelial cell, inconspicuous nucleoli, and inconspicuous cytoplasm) may be seen	None
Low-grade CMIL	PAM with mild atypia c-MIN (grades 2–4)	Yes	Predominantly basilar melanocytic proliferation with low-grade atypia (dendritic or small to moderate size polyhedral, usually non-epithelioid melanocytes with round to irregular nuclear contours, often nuclear hyperchromasia, inconspicuous nucleoli, and inconspicuous or scant cytoplasm)	Lower
High-grade CMIL	PAM with moderate to severe atypia c-MIN (grade 5–10)	Yes	More confluent basilar and significant non-basilar proliferation of melanocytes with high-grade atypia (moderate to severe), evidence of intraepithelial nested and/or pagetoid growth, and epithelioid cell cytomorphology	Higher
	Melanoma in situ	Yes	The term melanoma in situ may be used for (1) the most atypical high-grade CMILs involving close to full thickness of the epithelium, (2) histologically obvious melanomas without documented evidence of subepithelial invasion	Highest

CMIL, conjunctival melanocytic intraepithelial lesion.