Clinical Presentation of Ocular Surface Squamous Neoplasia in Kenya

Abstract

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.

Risk factors for ocular surface squamous neoplasia in Kenya: a case–control study

“… There were missing data on allergic conjunctivitis (24 participants), occupational location , hat or sunglasses use and cigarette smoking . …”

“…The latter had two types of controls per case: patients attending the eye clinic for reasons other than OSSN, and patients originally recruited as cases but whose histology was non‐OSSN . UV radiation affects the nasal limbus more than other parts of the eye which explains why there is a higher proportion of both benign and malignant conjunctival lesions nasally than temporally . Although cases had worked for a shorter period at their current occupations (10 years vs .…”

“…It is unclear why the prevalence is not 1:1 in African series. The presentation of OSSN in SSA also is relatively more aggressive, with a short history of 3–8 months compared to one year in temperate climates , and younger age of onset (30–40 years in SSA vs . 60–70 years in temperate climates) .…”

HIV-associated malignancies in sub-Saharan Africa

“…Diagnostic pathology in SSA is also limited, and often under-utilized when it exists [9]. Even for superficial tumors which can be visualized and often are diagnosed clinically in SSA, like Kaposi sarcoma (KS) and ocular surface squamous neoplasia (OSSN), clinical diagnosis performs poorly compared to pathology with positive predictive value less than 80% [10*, 11*]. For more visceral tumors, not only pathology limitations but inadequate surgical or interventional capabilities to obtain diagnostic tissue results in these tumors also being underrepresented.…”

Clinical characteristics, HIV status, and molecular biomarkers in squamous cell carcinoma of the conjunctiva in Ghana

“…This study was the first to assess the demographics, clinical characteristics, and tumor biomarkers in CSCC in Western Africa. Previous studies on CSCC in Africa describe that clinical characteristics of all ocular neoplasms do not separately analyze the characteristics of HIV+ and HIV− patients or are conducted in Eastern Africa . Additionally, other studies of CSCC in Africa report a higher rate of HIV infection in patients with CSCC than in the general population, ranging from 50% to 76.9% of the CSCC population with HIV infection .…”