Background: Pilomatrixoma is a benign tumor that arises from matrix cells of hair follicles. In ophthalmology, pilomatrixoma is relatively rare, yet there are reports on eyelid pilomatrixomas that were visible and/or palpable. Our case is the first report on pilomatrixoma that was found as a subconjunctival lesion and neither readily visible or palpable.
Case: A 32-year-old woman presented with a chief complaint of conjunctival hyperemia of the left eye with sensation of foreign body. A previous doctor suspected allergic conjunctivitis, but the prescribed antihistamine treatment had failed. Physical exam revealed hyperemia localized to the left temporal bulbar conjunctiva, as well as a 5 mm-diameter hard mass located underneath the lateral palpebral conjunctiva. With a suspicion of inflammatory reaction to a foreign body, enucleation of the mass was performed by opening and detaching the conjunctiva using surgical scissors.
Findings: The mass was hard, spherical and 5 mm×10 mm in size without adhesions. The pathology revealed hair follicles, basophilic cells, as well as shadow/ghost cells, which led to the definitive diagnosis of pilomatrixoma.
Conclusion: Pilomatrixoma is a benign tumor that arises from matrix cells of hair follicles. This case shows that pilomatrixoma from lateral canthus can extend underneath the conjunctiva.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 120: 791-796, 2016.