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Conjunctival Pigmented Lesions
Nevi
- Usually appear in childhood
- Maybe pigmented or non-pigmented
- May become more pigmented with puberty or pregnancy
- Appearance
- well circumscribed
- cystic spaces
- Vascular supply
- Categorized histologically as
- Junctional
- Compound
- Subepithelial
Lesions arising from melanocytes
Complexion Associated Melanosis (CAM)
- Bilateral perilimbal pigmentation in darkly pigmented inviduals
- Doesn't progress to melanoma
Primary Acquired Melanosis (PAM)
- Usually seen in fair skinned middle aged or older
- flat, unilateral, patchy, golden yellow or brown area, which may extend onto the cornea or corneal may similarly be involved.
- PAM with atypia can progress to melanoma
- PAM without atypia is low to no risk of transformation
- Treatement
- smaller lesions can be monitored, watching for nodularity, thickening, vascularity
- if changes or larger lesion, excision is recommended
- Excision
- Margins 4-5 mm
- Double freeze-thaw slow cryotherapy applied to the conjunctival edges
- For corneal PAM, apply absolute alcohol for one minute then epitheliectomy
- For diffuse disease or tarsal conjunctiva
- Cryotherapy with double freeze-thaw
- Topical mytomycin C 0.02% or 0.04%
- QID x 1 week
- Pause 1-2 weeks
- then QID x 1 week
- Repeat above until the pigment resolves, usually for 2-3 cycles
- punctual plugs placed before treatment
- use artificial tears and topical steroids for corneal toxicity
Malignant Melanoma
- Patients are usually 60-70 years old
- Limbus most common but can appear in the caruncle, tarsus or fornix
- Raised mass with feeder vessels
- Treatment
- Avoid incisional biopsy to prevent tumor seeding
- Excision with dry no-touch technique with margins of 4-6 mm
- Cryotreatment to conjunctival edges with double freeze-thaw
- Absolute alcohol to corneal lesions with
- Sclerectomy may be needed for tumors adherent to the sclera applying cautery and cryotherapy to the base
- Closure with primary closure or amniotic graft to cover the defects
- Sentinel node biopsy should be considered for lesions larger than 2 mm or high risk features on histopathology
- Prognosis
- Local recurrence 45% at 5 years and 59% at 10 years
- Mortality: 5-17% at 5 years- 9-35% at 10 years
- Denovo lesions have worst prognosis
- Poorer survival: older age, male, non-white, tumors with nodularity or ulceration.
Summary Table
| Type | History | Color | Appearance | Laterality | Specific Features | Chance of Maligancy | Primary Management |
|---|---|---|---|---|---|---|---|
| Nevus | Onset in childhood | Iight brown or non-pigmented | slightly raised and cystic with well defined margins | most unilateral and solitary | pigmentation changes with puberty and pregnancy | rare | Photograph and observe every 6-12 months |
| CAM | In darkly pigmented individuals, can increase with age | Brown | flat, non-cystic, diffuse, will-defined margins, usually prominent around limbus | bilateral | can be extensive | rare | Photograph and observe every 6-12 months |
| PAM | Newly pigmented | light to dark brown | flat, diffuse and non-cirumscribed | unilateral, usually in those with lighter skin color | waxing and waning of size and pigmentation | 50% with cellular atypia | If larger than 2 clock hours: wide excision with cryotherapy, if not possible map biopsy |
| Melanoma | Denovo or arises from previous lesion above | dark brown but may be amelanotic or mixed pigmentation | elevated, thickened, nodular | unilateral | highly vascular with feeder vessel often | 35% develop metastasis by 5 years | Complete excision with cryotherapy, metastatic workup |