Internal medicine

Retrospective cohort study

Melanoma

Visual acuity

Ophthalmology

Dermatology

Fornix

Hippocampus

Ocular Melanoma

Nevus

Cancer research

Medicine

To investigate clinical features and outcomes of conjunctival melanoma classified by tumour origin. Retrospective review of conjunctival melanoma patients at a single ocular oncology centre between April 18, 1974 and September 9, 2019. Lesions were divided into three tumour origin groups (primary acquired melanosis [PAM], nevus, and de novo) and clinical features and outcomes were compared. There were 629 patients with conjunctival melanoma that arose from PAM (n = 476, 76%), nevus (n = 59, 9%), or de novo (n = 94, 15%). A comparison (PAM vs. nevus vs. de novo) revealed patients with tumours arising from PAM presented with older mean age (62 vs. 52 vs. 55 years, p < 0.001), worse initial logMAR visual acuity (Snellen equivalent 20/30 vs. 20/25 vs. 20/25, p = 0.03), and greater clock hour involvement (4.8 vs. 4.0 vs. 3.2, p < 0.001). Tumours arising from nevus had lower frequency of fornix (31% vs. 9% vs. 24%, p = 0.02) and tarsal involvement (29% vs. 9% vs. 26%, p = 0.046) and more frequent classification as AJCC category T1 (60% vs. 89% vs. 62%, p = 0.01). After follow-up of (57.2 vs. 68.2 vs. 51.7 months, p = 0.35), tumours arising from PAM had worse mean final visual acuity (20/50 vs. 20/40 vs. 20/40, p = 0.02) and greater frequency of visual acuity loss ≥3 lines (25% vs. 15% vs. 10%, p = 0.02). Kaplan–Meier estimates for 5-year risk showed no difference by tumour origin for visual acuity loss ≥3 lines, local tumour recurrence, exenteration, metastasis, or death. Conjunctival melanoma most often arose from PAM, and tumour origin did not affect clinical outcomes.

Conjunctival melanoma: outcomes based on tumour origin in 629 patients at a single ocular oncology centre