Apparent Corneal Displacement Of A Conjunctival Naevus Associated With Pterygium Progression: A 25-Year Serial Photographic Case Report

This case highlights the value of long-term photographic surveillance in distinguishing passive mechanical displacement from true melanocytic proliferation of a conjuntival naevus with corneal displacement associated with a pterygium. 

We report a man in his late twenties presenting with a nasal pigmented conjunctival lesion in his right eye, his only seeing eye, clinically consistent with a conjunctival naevus. The lesion remained confined to the conjunctiva for nearly a decade before apparent corneal extension occurred following development and progression of a pterygium. Serial photographs over 25 years show corneal involvement only after pterygium formation, with stable morphology and no malignant features.

In 2000, a man in his late twenties presented with an asymptomatic pigmented lesion in his right eye (RE), his only seeing eye following traumatic loss of the left eye seven years earlier. Best-corrected visual acuity was 6/4 in the RE and no perception of light in the left eye. Slit-lamp examination showed a well-circumscribed, minimally elevated, uniformly pigmented lesion on the nasal bulbar conjunctiva with intralesional epithelial cysts, consistent with a conjunctival naevus. No feeder vessels, haemorrhage, nodularity or surface irregularity were present. The lesion remained stable in the interim without corneal involvement. In 2009, a triangular fibrovascular proliferation extending from the nasal conjunctiva onto the cornea was observed, consistent with early pterygium. Over subsequent years the pterygium progressively extended onto the cornea. In parallel, the pigmented lesion demonstrated gradual anterior displacement in the same direction. Later images suggested apparent corneal involvement; however, the lesion remained contiguous with the conjunctival component and preserved its morphology, pigmentation pattern, and intralesional cysts. Over 25 years of follow-up, the lesion showed no enlargement, architectural distortion, or suspicious vascularity, and the patient remained asymptomatic. Given the absence of malignant features and the RE being the patient’s only functional eye, the lesion was managed conservatively with serial observation and clinical photography.

Corneal extension of a pigmented conjunctival lesion does not necessarily indicate malignant transformation. Progressive pterygium may cause passive anterior displacement of adjacent conjunctival tissue, including pre-existing melanocytic lesions. Longitudinal clinical photography and imaging are therefore essential to distinguish mechanical displacement from true melanocytic proliferation and to support conservative management when no suspicious features are present.