Keratoacanthoma of the conjunctiva - case report and review of the literature.

INTRODUCTION: Keratoacanthoma (KA) is a relatively common, benign, rapidly growing and self-limiting squamous proliferation, which appears most frequently on the sun-exposed skin. The nature of KA and its relationship to squamous cell carcinoma (SCC) still represent one of the major debates in dermatopathology, as it is the truthfulness of such a diagnosis outside the skin. However, the tumor is now known to originate from the pilosebaceous units of the skin or from ectopic sebaceous glands of squamous mucous membranes, and to differentiate onto follicular isthmus÷infundibulum-like epithelium.

CASE PRESENTATION: A 71-year-old man presented with a sore and red right eye, which on slit-lamp biomicroscopical examination revealed a dome-shaped lesion at the temporal inferior conjunctival limbus. After a thorough histopathological examination, a diagnosis of KA has been made, both after the initial tumor excision and after the relatively rapid recurrence. After the second intervention, no recurrence was observed over five years of follow-up, confirming the diagnosis.

CONCLUSIONS: The peculiarity of the case stands in his exceptional rarity, being to our knowledge the first conjunctival KA reported in our country. In the light of current knowledge, the peculiar limbal location of all the conjunctival KAs reported in the literature raised the question of the possible role of limbal stem cells in the histogenesis of these tumors, similar to the pilosebaceous ones. The treatment of conjunctival KA remains the complete excision of the tumor, as it allows histopathological evaluation of the entire tumor and the exclusion of a KA-like SCCs or KAs with SCC component.