Here we present an unusual case of an epithelial implantation cyst within the orbit which presented 40 years after initial injury from an airgun pellet. A retrospective review of the case was performed. This case highlights the importance of taking a thorough history when assessing adnexal lesions of undetermined origin.
A 69-year-old Caucasian man presented with a two week history of diplopia on upgaze and right upper lid swelling. His only history of note was of an airgun injury to his right orbit 40 years ago which required surgical removal of the pellet.
His corrected Snellen visual acuity was 6/5 bilaterally. There was a right superomedial orbital swelling not involving the eyelid margins (
Magnetic resonance imaging (Figures 2 and 3) showed a non enhancing soft tissue lesion in the anterior superior quadrant, 26 mm in maximum dimension. The mass was extraconal and displaced the right globe laterally. Anteriorly it was indistinguishable from the subcutaneous tissue and appeared to be intimately related to the inferior aspect of superior oblique. It demonstrated high signal characteristics on T1 and low signal on T2.
A chest x-ray and routine haematological investigations were normal.
An explorative excision biopsy was undertaken. Histological analysis confirmed keratinising squamous epithelium, and flattened double-layered epithelium which had no specific distinguishing features. There were no skin appendage structures suggestive of a dermoid. These features are consistent with a diagnosis of an epithelial implantation cyst arising from orbital trauma 40 years previously.
This case highlights the problems with diagnosing adnexal lumps. A nasolacrimal apparatus lesion was considered in our differential but no involvement of the nasolacrimal system was found on surgical exploration. Similarly imaging showed no sinus involvement, thus excluding a mucocoele as a potential diagnosis.
Epithelial implantation cysts are a rare complication of orbital surgery or trauma. These cysts are epithelial lined
structures found within the subcutaneous tissues or deeper structures and are separated from the normal epithelium. They arise secondary to delivery of epithelial cells to deeper areas following tissue manipulation.
Epithelial implantation cysts after squint surgery are a rare but recognised late complication which can present decades after the initial surgery [
Presentation with implantation cysts can occur several decades following elective surgery. Song et al. [
The risk factors for development of implantation cysts are unknown. We hypothesise that trauma is more likely to give rise to cyst formation than elective surgery. As in our case, we believe that injuries in which a foreign material has been embedded in deeper tissues are more likely to carry epithelial cells to deeper layers. Surgical technique in debriding and closing of these wound is also likely to play a role in development of cysts.
Our case is the first to report epithelial cyst formation following an airgun pellet injury. It is apparent that obtaining a thorough history of childhood surgery and trauma is vital in diagnosing adenexal lesions.
We would like to acknowledge Dr. Alan Cunningham MBBS FHEA for his support.