Ocular Surface Squamous Neoplasia: From Blue Skies to Blue Dyes—We Still Need Our Ophthalmic Pathologists

Withoutquestion,ocular surface squamousneoplasia (OSSN) is a solar-related condition, particularly endemic in immunosuppressed patients.1-3 This viral-related tumor of the conjunctival surface epitheliumtends tooccur in sun-exposed regionsof theeye,mostoftenat the nasal or temporal limbus.This tumorcanhaveproteanclinicalmanifestationsas a gelatinous, translucent, foamy, leukoplakic, vascular, or pigmentedmass.3,4 Risks for tumor growthonto the cornea, into the fornix, and rarely into the orbit, producing ultimate risk for metastatic disease, are understood. Treatment paradigms have shifted over the past 20 years from exclusive surgical removal using the “notouch” techniquewith superficial corneal epitheliectomyand conjunctival cryotherapy3 to surgical or nonsurgical strategies using topical antitumor medications such as mitomycin C, 5-fluorouracil, interferon alpha-2b (also available as injection), cidofovir, photodynamic therapy, and even more curious methods, including topical aloe vera.3,5-7 The goal of therapy is complete eradication of this low-grade malignancy to prevent recurrence, orbital invasion,metastatic disease, and death. In this issue of JAMA Ophthalmology, Gichuhi et al studied OSSN in Kenya and explored the accuracy of clinical diagnosis8 aswell as thepotential benefit of toluidinebluedye staining.9 They noted a tendency in Kenya tomanage this tumor based on clinical features alone without histopathologic confirmation because histopathology is relatively unavailable throughout Africa. They evaluated clinical diagnostic accuracy using tumor photograph interpretation by selected observers as compared with histopathologic findings. Of 496 patients with a conjunctival tumor examined, photographed, and excised, OSSN represented 187 cases (38%). Human immunodeficiency virus infection was found in 74% of patients with OSSN. Despite some classic features, tumor photographic interpretation led to only 54% positive predictive value, which is only minimally better than chance. Gichuhiet al foundOSSN(comparedwithnon-OSSNcases) tended to show features of large tumor size, temporal limbal location, circumlimbal ring, inflammation, and leukoplakia. However, there were 2 findings in their series that strikingly differed from non-African series, including tumor pigmentation in 53%of cases and orbital invasion in 1%, both quite uncommon in reports from the United States and Australia.1-7 In defense of their observations, it is truly difficult to differentiate OSSN from actinic keratosis and some pterygia, especially since they are parallel end points from chronic solar radiation,directing tomalignant, premalignant, orbenignoutcomes, respectively. Furthermore, determining a lesion status byphotographyalone is not the equivalent of slitlampbiomicroscopy and face-to-face patient evaluation. So to improve diagnostic accuracy, Gichuhi et al focused on a second topic, in this issue of JAMA Ophthalmology, reRelated articles pages 1305 and 1314 Toluidine Blue 0.05%Vital Staining in Ocular Surface Squamous Neoplasia Original Investigation Research