Occurrence of lacrimal gland tissue outside the lacrimal fossa: comparison of clinical and histopathological findings.

Purpose: To analyse clinical referral diagnoses and the location of lesions with histologically verified lacrimal gland tissue occurring outside the fossa of the lacrimal gland.

Methods: Sections of lesions excised from areas outside the fossa of the lacrimal gland containing lacrimal gland tissue on histological examination were collected from the files of the Eye Pathology Institute, Copenhagen, Denmark. Specimens spanned a period of 50 years. Sections were re-examined and referral data on location and clinical diagnosis were compared with histological findings.

Results: A total of 120 lesions were collected. Of these, 59 (49%) consisted of prolapsed lacrimal gland. The remaining 61 (51%) lesions contained ectopic lacrimal gland tissue, either as part of a complex choristoma in 38 (32%) cases, or as solitary ectopic lacrimal gland tissue in 23 (19%) cases. The majority (97; 81%) of lesions had been located at the temporal epibulbar conjunctiva and included mainly prolapsed lacrimal gland and complex choristoma. The clinical referral diagnoses covered a wide spectrum of lesions. The most frequent clinical diagnoses were non-specific tumour (35%), non-specific cyst (18%) and dermoid (11%). Of the 61 lesions containing ectopic lacrimal gland tissue, only two had been preoperatively diagnosed as such and only two of the 59 lesions with prolapsed lacrimal gland had been correctly diagnosed.

Conclusions: Prolapsed palpebral lobe of the lacrimal gland was the most common lesion and, as expected, the prime location was the temporal conjunctiva. Despite this location, the referring clinical diagnosis was often wrong or non-specific. Surgeons seem to have been unaware of the various clinical manifestations of extrafossal glandular tissue, particularly when excising lesions in the upper temporal region of the conjunctiva. Surgical intervention in this location may jeopardize the excretory ducts of the lacrimal gland and may consequently lead to dry eye and thus should be avoided when the typical clinical appearance of prolapsed lacrimal gland is encountered.