Report of an unusual case of a conjunctival cyst with Liesegang rings.

Liesegang rings are laminated precipitation structures well recognized in the field of chemistry. We present a rare case of a 64-year-old man who sought examination for a conjunctival cystic lesion of several months' duration, located in the right nasal bulbar conjunctiva near the plica semilunaris. The lesion was excised completely and uneventfully under local anaesthesia. Histopathological examination revealed a large folded cyst in the substantia propria. The cyst contained multiple eosinophilic concentrically spherical and oval structures of variable size with an amorphous central core compatible with Liesegang rings. No fungal or parasitic organisms were identified. This is the first photographically documented case of Liesegang rings appearing in the conjunctiva. Liesegang ring formation should be taken into account during histopathological examination of a conjunctival cyst and not be misdiagnosed as a parasitic infection.