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Conjunctival melanocytic tumors comprise benign and malignant neoplasms.
Patients with conjunctival melanocytic lesions usually present when they recognize a new or growth of a preexisting lesion.
Diagnosis is by slit lamp and fundus examination, sonography or and photo-documentation.
Lesions can appear pigmented brown, tan, or non-pigmented.
Primary acquired melanosis usually occurs in middle-aged individuals.
Mostly affects Caucasians.
Conjunctival melanocytic lesions appear pigmented, are usually unilateral.
The lesions may become thickened over time.
Biopsy is recommended to define the diagnosis and appropriate management.
Conjunctival melanomas may arise from primary acquired melanosis, nevi, or de novo.
Conjunctival melanomas arise most commonly from primary acquired melanosis.
Conjunctival melanomas are more frequently observed in Caucasians.
Conjunctival melanomas may exhibit increased vascularity and adherence to the underlying sclera with nodular or diffuse growth.
Suspicious lesions are completely excised and submitted for histopathological analysis.
Multicentric lesions can occur, especially if associated with primary acquired melanosis.
Lesions consisting of primary acquired melanosis, and melanoma are also not uncommon.
A conjunctival malignant melanoma has invasion of melanoma cells into the subepithelial layers.
Some lesions that cannot be unequivocally assigned to a nevus, primary acquired melanosis, and are best classified as Indeterminate melanocytic proliferations of the conjunctiva.
Primary acquired melanosis are biopsied for histological examination.
Surgical margins can be treated with cryotherapy.
Treatment with topical mitomycin or interferon can be considered for histology-proven biopsied Primary acquired melanosis.
Malignant melanomas should be completely excised.
Adjunctive cryotherapy and additional treatment can be also employed.
Sentinel lymph node biopsy should be considered for lesions thicker than 2 mm.
Nevi are usually stationary but can exhibit growth due to hormonal changes or local inflammation.
Nevi should be observed for growth or change in color.
Primary acquired melanosis without atypia may be followed by observation.
Primary acquired melanosis with atypia require – after treatment – periodical follow-up by an experienced ophthalmologist to rule out recurrence or progression into malignant melanoma.
Patients with conjunctival melanoma should be periodically followed and investigated for local recurrence.
Systemic work-up is also mandatory for conjunctival melanoma.
Nevi are congenital lesions and only a small percentage progress into malignant melanoma.
Primary acquired melanosis with atypia has a high likelihood to progess into malignant melanoma in contrast to PAM without atypia (13%).
Conjunctival melanomas have a risk of 20-50% of local recurrence.
Conjunctival melanoma has a rate of mortality at 10 years ranging from 13 to 38%.
Melanoma involving the fornix or the palpebral conjunctiva have a higher risk for metastasis and locally aggressive disease than bulbar lesions.
Caruncular disease may infiltrate the orbit, and is associated with 50% mortality at 3 years.
Increased mortality is also seen with conjunctival melanoma lesions thicker than 2 mm.
de novo melanomas carry a higher risk of metastasis and death compared with those cases arising from primary acquired melanosis or nevus.