Orbital cyst of lacrimal sac derivation.

Orbital cyst from lacrimal sac epithelium is rare and thought to originate from diverticulum of the lacrimal sac. The cyst may have direct communication with the sac, or the two structures may be anatomically separate. Since these lesions most commonly present as a medial canthal mass, the differential diagnosis should include other disorders that may cause a mass in this region. A 42 year old woman presented with a two-year history of a mass in the right medial canthal region. Nasolacrimal system was patent on irrigation. Sophisticated radiological investigation utilizing dacryocystography and computed tomography combined with dacryocystography accurately localized the lesion and demonstrated its relationship to the nasolacrimal system. This tremendously facilitated surgical removal. The lesion was excised completely via anterior orbitotomy and submitted for histopathologic examination. Haematoxylin-eosin stains revealed a cystic cavity lined by pseudostratified columnar and cuboidal epithelium with interspersed goblet cells consistent with a cyst derived from lacrimal sac epithelium, located separately, but in close proximity to the lacrimal sac. The Authors present a patient with a mass in the righ medial canthal area histologically diagnosed as an orbital cyst of lacrimal sac epithelium derivation. Sophisticated radiological lacrimal investigation helps in detection, localization and in planning surgery.