Dentigerous Cyst Masquerading as Lacrimal Sac Diverticulitis.

Introduction: Dentigerous cysts (DCs) involving the orbit are extremely rare. The authors report a unique case of stand-alone orbital DC associated with ectopic canine tooth masquerading as a lacrimal sac diverticulitis with superadded preseptal cellulitis. Case Presentation: A 21-year-old lady presented with left inferomedial swelling, associated with pain and redness of 1-week-duration. A lacrimal sac diverticulitis with preseptal cellulitis was suspected and imaging was requested in view of progression. Computed tomography scan of orbit revealed a well-defined heterogenous mass, with associated hyperdense lesion within the mass, prompting a possibility of a foreign body granuloma. Surgical exploration and excision confirmed the diagnosis of an ectopic canine tooth with associated DC along with excessive adhesion of the cyst to the lacrimal sac wall. Maxillary sinus did not show any abnormality. Lacrimal irrigation was patent with no recurrence noted at 6-month follow-up. Conclusion: This report highlights the presentation of DC with associated ectopic canine tooth as an isolated orbital mass, initially manifesting as preseptal cellulitis with lacrimal sac diverticulitis. Recurrent episodes of infection can lead to synechiae formation, rendering adjacent lacrimal sac more prone to injury. Cyst excision with meticulous dissection yields good outcome.