Pigmented Conjunctival Lesions

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Differential of pigmented conjunctival lesion

Unilateral
Highly asymmetric
Non-cystic
Develops in lighter skinned people in middle age
Risk of progression
- More than 3 clock hours of pigmentation
- Caruncular, forniceal or palpebral involvement
- Cellular atypia (eg. prominent nucleoli, mitotic figures): most important
  - With atypia has 50% risk of transformation to melanoma within 5 years
  - Without atypia can by monitored every 6-12 months
Nodularity is a sign of malignant change
More than 2 clock hours of pigment is indication for removal
- Surgical excision and local scleral cryotherapy
Topical mitomycin C can be used for lesions too large to remove

Palpebral conj
Caruncular
Lid margin
Fornix
Deep invasion
Thickness >1.8mm
Pagetoid spread
Lymphatic invasion
Mixed cell type
De novo occurrence (rather than from PAM)
Sparing the limbus
Incomplete resection (excision should include a 2mm margin using a no-touch technique)

Present in first or second decade: typically congenital lesions that are amelanotic at birth but gain pigment at puberty.
Typically affect young Caucasian patients
50% contain epithelial inclusion cysts (which are rarely seen in melanomas)
Frequently involve nasal or temporal limbus
33% have feeder vessels
Rarely on palpebral conj: these lesions should generally be biopsied
Classified based on location with tissue
- Epithelial
- Junctional
- Subepithelial/stromal
- Compound (within more than one layer)
Excision should be considered if growth occurs

Unilateral
Young adults
Lesion is subepithelial ie. scleral or episcleral
Associated adjacent dermal pigmentation: naevus of Ota and perhaps on should (naevus of Ito)
Risk of uveal melanoma (but not conjunctival melanoma)
Associated with glaucoma