Importance
There is a trend towards treating conjunctival lesions suspected to be ocular surface squamous neoplasia (OSSN) based on the clinical impression.
Objectives
To describe the presentation of OSSN and identify clinical features which distinguish it from benign lesions and subsequently evaluate their recognisability.
Design, Setting and Participants
Prospective multi-centre study in Kenya from July 2012 through July 2014 of 496 adults presenting with conjunctival lesions.
Exposures
Comprehensive history, slit lamp examination and photography before excision biopsy. Frequency of clinical features in OSSN and benign lesions recorded. One histopathologist examined all specimens. Six additional masked ophthalmologists independently examined photographs from 100 participants and assessed clinical features.
Main Outcomes and Measures
Proportions and means were compared using Chi-square, Fisher’s exact test or t-test as appropriate. Inter-observer agreement was estimated using Kappa statistic. Examiners’ assessments were compared to a reference.
Results
Among 496 participants, OSSN was the most common (38%) histological diagnosis, followed by pterygium (36%) and actinic keratosis (19%). OSSN cases were slightly older and tended to have lower levels of education than benign ones. Females predominated (67% of OSSN vs 64% of benign lesions; P = .65). HIV-infection was common among OSSN cases (74%). The commonest location was the nasal limbus (61% OSSN vs 78% benign lesions; P < .001). Signs more frequent in OSSN included; feeder vessels, odds ratio [OR], 5.8 [95%CI, 3.2-10.5]; moderate inflammation, OR, 3.5 [95%CI,1.8-6.8]; corneal involvement, OR, 2.7 [95%CI,1.8-4.0]; leukoplakia, OR, 2.6 [95%CI,1.7-3.9]; papilliform surface, OR, 2.1 [95%CI,1.3-3.5]; pigmentation, OR, 1.5 [95%CI, 1.0-2.2]; temporal location, OR, 2.0 [95%cI, 1.2-3.2]; circumlimbal location, (7.0% vs 0.3%; P<.001); severe inflammation (6.0% vs 0.3%; P <.001) and larger mean [SD] diameter (6.8 [3.2]mm vs 4.8[2.8]mm; P < .001). All OSSN signs were also observed in benign lesions. There was slight to fair inter-observer agreement in assessment of most signs and diagnosis (Kappa, 0.1-0.4). The positive predictive value of clinical appearance in identifying OSSN was 54% (interquartile range, 51-56) from photographs where prevalence was 32%.
Conclusions and Relevance
With overlapping phenotypes and modest inter-observer agreement, OSSN and benign conjunctival lesions are not reliably distinguished clinically. Point-of-care diagnostic tools may help.
