Investigating Clinically Invisible Ocular Surface Squamous Neoplasia ( OSSN ) in Pterygium Excisions

BACKGROUND: To determine the prevalence of clinically unsuspected ocular surface squamous neoplasia (OSSN) in pterygia excised in a high ultraviolet (UV) exposure region of Australia. METHODS: Retrospective cross-sectional prevalence study of all primary pterygium excisions by a single surgeon on the Sunshine Coast, Queensland, between October 2019 and March 2023. Of 174 procedures screened, 125 specimens were included: lesions at least 2.0 mm from the limbus, clinically diagnosed as benign. Eyes with pre-operative suspicion of OSSN, recurrent pterygium, non-conjunctival lesions and those without a retrievable histology report were excluded. All specimens were submitted for histopathology regardless of appearance; any epithelial dysplasia or carcinoma in situ was classed as OSSN-related pathology. Age and sex were compared using t-tests and chi-square tests; prevalence is reported with Wilson score 95% confidence intervals (CI). RESULTS: Of 125 specimens (42 women, 83 men; mean age 63.6 ± 12.7 years), 24 (19.2%; 95% CI, 13.3-27.0) showed OSSN-related changes: carcinoma in situ in 4 (3.2%; 95% CI, 1.3-7.9), moderate-to-severe dysplasia in 5 (4.0%; 95% CI, 1.7-9.0), and low-grade dysplasia in 15 (12.0%; 95% CI, 7.4-18.9). Dysplasia was more common in men (21.7% vs. 14.3%) and in older patients, though neither difference reached significance (p = 0.321 and 0.288). No included lesion was recorded as clinically suspicious pre-operatively. CONCLUSIONS: Histopathology identified dysplastic or in situ change in nearly one in five clinically benign pterygia from this high-UV population. These findings support submitting excised pterygium tissue for histopathological examination, particularly where UV exposure is intense.