Ocular surface squamous neoplasia (OSSN) is a spectrum of dysplastic changes including precancerous and cancerous epithelial lesions of the conjunctiva, cornea and limbus with significant ocular morbidity and mortality [1]. It encompasses dysplasia, Conjunctival Intraepithelial Neoplasia (CIN) and squamous cell carcinoma (SCC) [2].  CIN is more prevalent than SCC accounting for 4% of conjunctival lesion, whereas the incidence of SCC is only 0.02 to 3.5 per 100000 population [3]. Around 75% OSSN cases occur in men, 75% are diagnosed in elderly (average 56-60 years) age group and more than 75% of the tumours occur the limbus [4].

The disease has a predilection towards dark-skinned Caucasians [5], those with prolonged sunlight exposure, ultraviolet radiation, HPV (type 16, 18) infections and AIDS [6,7]. Immune dysregulation syndromes like non-Hodgkin’s lymphoma, atopic diseases, ocular cicatricial pemphigoid, post-organ transplantation, xeroderma pigmentosa and Papillon–Leferve syndrome can also predispose to OSSN [8-13]. The modifiable risk factors associated with this condition include exposure to petroleum products, chemicals (trifluridine, arsenic, beryllium), heavy smoking, vitamin A deficiency, chronic inflammation and Hepatitis C infection [2,7,14,15]. Mutations affecting the tumor suppressor gene p53 (high percentage of CC>TT alterations) in majority and Bcl-2 immunoexpression in minority has been reported [16].

OSSN is mostly unilateral but maybe bilateral in immunocompromised individuals. The presenting features are redness and irritation in majority of cases whereas vision can be affected in lesions obscuring the visual axis. Morphologically, it appears as a fleshy or nodular, sessile minimally elevated mass with surface keratin, feeder vessels, and secondary inflammation. [1,2] Extension of the tumor onto the adjacent cornea may be in the form of a relatively avascular superficial grey opacity or as a diffuse gelatinous or papilliform lesion. [17]

The treatment modalities include excision biopsy (tumor free margin of atleast 4 mm) with “no-touch” technique, cryotherapy with or without topical chemotherapy using mitomycin C (MMC) or 5-fluorouracil(5-FU), topical immunomodulators like interferon alpha-2b (IFN α2b), topical drugs like Cidofovir, Bevacizumab and Retinoic acid. [1-3,18] Corneal portion of the mass is usually managed by controlled alcohol keratoepitheliectomy. [19] Lee and Hirst reported a 17% recurrence after excision of conjunctival dysplasia, 40% after excision of CIN and 30% for SCC of the conjunctiva. However, with modern protocol‑based management, the local recurrence rate can be reduced to below 5% with a regional metastasis rate of 2%. [1,2,19]

Case report – A 61-year-old male patient presented with a mass in the right eye for last 7 years. It was painless in nature with a indolent course associated with intermittent redness. There was no association with pain, bleeding or limitation of movements. There was no history of trauma or any significant medical or surgical illness. On examination, the best corrected visual acuity (BCVA) was 6/6 for distance and N-6 for near in both eyes. Intraocular pressure in both eyes was 19 mmHg on Goldman’s Applanation Tonometer. Slit lamp examination of the right eye revealed a 4X4mm pedunculated mass at limbus from 8 o’ clock to 9 o’ clock without any overlying vessel. The mass was not attached to underlying sclera and encroached 2 mm onto the cornea (Fig 1).

Figure 1: Preoperative slit-lamp photograph showing a pedunculated limbal mass encroaching onto cornea

Anterior chamber was uniformly deep with Von Herick’s grade 3 with round, regular pupil briskly reacting to light and clear lens. The anterior segment of the left eye was within normal limits. Dilated fundus examination showed a cup-disc ratio (CDR) of 0.3:1 with a dull foveal reflex and normal periphery in both the eyes. Complete hemogram showed a Hb of 13g/dL, fasting blood sugar of 106 mg/dL, post prandial blood sugar of 128 mg/dL, non-reactive serology, normal coagulation profile and regular sinus rhythm on ECG (12 leads). The differential diagnoses were pingeculitis, nodular episcleritis, pyogenic granuloma and OSSN. The patient was then planned for excision and biopsy. Under local anaesthesia and strict aseptic measures, the entire mass was excised by “no-touch” technique. A margin of 5 mm from conjunctival border and 2 mm from corneal border, were resected. Mitomycin C (0.02%) was applied for 3 mins at the base to minimise seeding and prevent recurrence. Absolute alcohol (70%) was used for localized corneal epitheliectomy and the small defect was filled by primary closure with 8-0 polyglactin 910 suture. The excised tissue was sent for histopathological examination. On postoperative day 1 (Fig 2), eye patch was removed, and patient was started on topical Moxifloxacin (0.5%) + Prednisolone acetate (1%) 6 times a day with gradual tapering over 4 weeks.

Figure 2: Slit-lamp photograph on postoperative day 1

Histopathological report showed tissue bits lined by stratified squamous epithelium which demonstrated disordered maturation, nuclear polymorphism, hyperchromasia and increased mitotic activity. A mild degree of chronic inflammatory cell infiltrate was seen in the stroma. There were dysplastic changes involving full thickness in some areas. The basement membrane was intact throughout and there was no evidence of stromal invasion. (Fig 3).

Figure 3: Histopathology of the mass (H&E 4X) showing tissue bit lined by stratified squamous epithelium with full thickness dysplasia and an intact basement membrane (arrows) (a) H&E 20X section showing disordered maturation, nuclear pleomorphism and hyperchromasia of epithelial cells (b)

 The patient was referred to the medical oncology and radiation oncology departments where a routine follow-up was advised. On subsequent visit, the wound was completely healed, and no recurrence was noted upto 4 month (Fig 4).

Figure 4: Slit-lamp photograph showing adequate wound healing and restoration of ocular surface at postoperative 1 month (a) and postoperative 4 months (b)