Lacrimal Gland and Nasolacrimal Drainage Apparatus

Lesions of the lacrimal gland usually present as a palpable mass in the superotemporal orbit. Of these, approximately 50% are inflammatory and the other 50% represent various types of tumors. Lacrimal gland tumors occur in approximately 1 in one million people each year. More than half of the lacrimal gland tumors are epithelial in origin. Of the epithelial tumors, about 50–60% are benign and include pleomorphic adenoma and oncocytoma. The other 40–50% are malignant, with approximately 90% being adenoid cystic carcinoma and adenocarcinoma. Another one-third of lacrimal tumors are lymphoid lesions. The remaining 10–15% are mesenchymal, arise from distant metastases, or occur via direct extension from another site. Epithelial tumors account for the majority of nasolacrimal drainage apparatus (NLDA) tumors, followed by mesenchymal tumors, lymphoid lesions, melanoma and other lesions including infection. The role of the radiologist is to assess the imaging appearance of the lacrimal lesion, which may aid in narrowing the differential diagnosis.