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Figure 1

Figure 2

Figure 3

All photos courtesy of: LV Prasad Eye Institute
Used with permission. Not to be reproduced.

A 28-year-old man complained of off-and-on redness, photophobia and burning sensation in the right eye for the past 6 years [Figure 1]. There was a history of frequent usage of medications and photo-therapeutic keratectomy 2 years back, with no significant improvement. Slit lamp examination [Figure 2] revealed temporal conjunctival congestion, with epithelial haze of the cornea. Anterior chamber and fundus examination through the nasal cornea was normal. The left eye was essentially within normal limits.

1.	What could be the most appropriate differential clinical diagnosis?
	d -- any of the above Microbial infection with low virulence or chronic use of non-specific topical medications could lead to a similar clinical picture.
2.	Surprisingly, the final diagnosis on this patient was ocular surface squamous neoplasia. What is the best diagnostic tool for this?
	a -- corneal scraping Corneal scraping would show the loss of polarity and dysplasia of cells suggestive of squamous neoplasia. IFA and culture would prove microbiological infection. Impression cytology shows only surface changes and not the exact depth of corneal involvement. Thus, treatment might be inadequate, if based only on surface impression.
3.	The best management is:
	c -- (a) + edge cryo and 3 monthly follow up Excision biopsy of conjunctival lesion, alcohol assisted excision of corneal component and edge and base cryotherapy would be the best management, followed by 3 monthly follow up for the first 3 years. A trial of topical MMC or Interferons treatment might be favoured by some physicians, but looking at the chronicity of lesion for the past 6 years, this might not be a suitable choice. On regular follow up, if the lesion shows any sign of recurrence, topical MMC or Interferon might be tried. Rose Bengal staining would be helpful to pick early recurrence.

Ocular Surface Squamous Neoplasia (OSSN) may present simulating several lesions of the ocular surface including – pingecula, pterygium, chronic conjunctivitis, corneal ulcer, pyogenic granuloma, etc. High degree of clinical suspicion for OSSN is warranted in a case of corneal ulcer with conjunctival mass if the lesion is highly vascular with episcleral feeder vessels [Figure 3] and does not respond to conventional treatment, especially in patients with xeroderma pigmentosa or reactive for HIV.

Reference:

1. Lee GA, Hirst LW. Ocular surface squamous neoplasia. Surv Ophthalmol. 1995 May-Jun; 39(6):429-50.