Ectopic Lacrimal Gland Tissue: A Systematic Review

Purpose: To review the clinical and histopathological findings associated with ectopic lacrimal gland tissue. Methods: A systematic review of the literature on ectopic lacrimal gland tissue was performed. Studies which met clinical and histolopathological criteria for ectopic lacrimal gland tissue written in English and published in peer-reviewed journals were included. Results: Sixty-nine publications detailing 180 cases of ectopic lacrimal gland tissue were published between 1946 and 2018. Males were affected slightly more than females (57% vs. 43%) and 95% cases were unilateral. Patients presented at a mean age of 21 years, most commonly with a mass, although orbital lesions commonly presented with proptosis. The most common location for ectopic lacrimal gland tissue was epibulbar conjunctiva (62%), other locations included orbital (16%), eyelid (11%), intraocular (9%), lacrimal sac (2%), and nasal mucosa (0.6%) sites. Most lesions (86%) were locally resected. The most common histological types were complex choristomas (56%) and simple choristomas (38%). However, neoplastic transformation to pleomorphic adenoma (5%), adenocystic carcinoma (0.6%), and adenocarcinoma (0.6%) was reported. Conclusions: Ectopic lacrimal gland tissue is rare but should be considered in the differential diagnosis of masses in the epibulbar conjunctiva, eyelid, orbit, and lacrimal sac, particularly in childhood, as the diverse way it presents means that it may mimic more common choristomas. It can undergo neoplastic transformation in the same way as can the lacrimal gland and incomplete excision can result in recurrence.