Magnetic resonance imaging of unilateral lacrimal gland lesions

To report the findings on magnetic resonance imaging (MRI) of various benign and malignant unilateral lacrimal gland lesions.

This is a retrospective noncomparative interventional case series. Thirty-one consecutive patients with a unilateral lacrimal gland lesion were analyzed. The preoperative MRI findings were correlated with the pathology results. The main outcome measures were anatomic extent, configuration, margins, angulation, internal features on T1- and T2-weighted images (with respect to extraocular muscles and cerebral gray matter), contrast enhancement of the lesion and adjacent bone change on MRI.

Of the 31 patients, 21 had chronic dacryoadenitis, 3 had lymphoid tumors, and 7 had epithelial tumors including pleomorphic adenoma (3), adenoid cystic carcinoma (3), and pleomorphic adenocarcinoma (1). The results of the patients with chronic dacryoadenitis demonstrated involvement of the orbital lobe alone in 13 patients (62%), involvement of both orbital and palpebral lobes in 8 (38%), a molded configuration with ill-defined margins, sharp angles in 13 (62%), round angles in 8 (38%), lack of bone change, an isointense internal signal on T1-weighted images, a hypointense signal on T2-weighted images, and moderate contrast enhancement. The patients with lymphoid tumors demonstrated involvement of the orbital lobe, a molded configuration with ill-defined margins and sharp angles, lack of bone change, an isointense internal signal on T1-weighted images, an isointense signal on T2-weighted images, and moderate contrast enhancement. Those with epithelial tumors showed involvement of the orbital lobe, a well-circumscribed oval configuration, and round angles. Pleomorphic adenoma demonstrated smooth margins, bone expansion in two patients , and no bone change in one. Adenoid cystic carcinoma and pleomorphic adenocarcinoma showed irregular margins and bone destruction. All epithelial tumors demonstrated an isointense internal signal on T1-weighted images, a hyperintense signal on T2-weighted images, and moderate contrast enhancement.

It is difficult to uniformly correlate the MRI features and histopathologic findings in lacrimal gland lesions. However, MRI seems to be useful in determining the etiology of a unilateral lacrimal gland lesion. Internal tissue features on T1- and T2-weighted images of MRI are most helpful in categorizing these lesions. Although the number of patients is small, our findings suggest that there are differences in orbital MRI findings of inflammatory lesions and lymphoid tumors as compared to benign and malignant epithelial tumors in the lacrimal gland fossa.