Clinical, CT, and MR Findings for the Pretreatment Diagnosis of Primary Epithelial Tumors of the Lacrimal Gland.

INTRODUCTION/BACKGROUND: The diagnosis of benign and malignant primary epithelial tumors of the lacrimal gland (PET-LG) is challenging. This study was designed to obtain a pretreatment diagnosis of adenoma and Adenoid Cystic Carcinoma (ACC) of the LG based on clinical and imaging features. MATERIALS AND METHODS: A retrospective analysis was conducted on 18 patients with histologically confirmed PET-LG (6 adenomas and 12 ACCs). Demographic data, clinical outcomes, and imaging findings were collected. MR findings included lesion size, signals, contrast enhancement patterns, DWI/ADC values, and evidence of orbital involvement. For ACC cases, CT findings were compared with MRI findings using pathological evidence as the reference. Statistical analyses were performed to assess differences between the adenoma and ACC groups. RESULTS: ACCs showed a more aggressive imaging pattern than adenomas. Compared with adenomas, ACCs were larger at presentation and more frequently demonstrated vivid contrast enhancement, orbital wall destruction, and extraocular muscle involvement. Among these findings, orbital wall invasion and extraocular muscle involvement were the most robust imaging features associated with ACC. In contrast, adenoma more commonly showed smooth orbital wall erosion or remodeling. For assessing bone invasion in ACC, MRI showed higher sensitivity and accuracy than CT, whereas CT remained useful for evaluating cortical bone changes. DISCUSSION: Imaging findings can be used to diagnose benign and malignant PET-LG. MRI plays a pivotal role in identifying these imaging features for clinical staging, but CT remains valuable for detecting bone erosion. CONCLUSION: We suggest applying both CT and MR of the orbit as imaging techniques to enhance pretreatment planning.