Magnetic resonance diffusion-weighted imaging in lacrimal gland lymphoma versus inflammation: A comparative study

To determine the role of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) in differentiating the inflammatory process and malignant lymphoma of the lacrimal gland. A retrospective analysis of all subjects who underwent lacrimal gland biopsy and magnetic resonance (MR) imaging with DWI sequences during a 10-year period at the Sheba Medical Center, Israel. The lacrimal glands' ADC values were documented bilaterally by blinded observers and correlated with the final histology verified diagnoses. Twenty-eight patients were included, with 19 females (68%) with a mean ± SD age of 48.1 ± 25.7 years. The right orbit was involved in 14 cases (50%) and the left in 13 (46%); one patient (4%) had bilateral involvement. Seventeen cases (61%) had a final diagnosis of idiopathic inflammation or dacryoadenitis, and six cases (21%) were diagnosed with lymphoma. Additional diagnoses included pleomorphic adenoma in 3 (11%), adenoid cystic carcinoma, and solitary fibrous tumor. Lower mean ADC values were observed in the lymphoma versus inflammatory group (1.03 × 10-3 Vs. 1.45 × 10-3, P = 0.02). Restricted diffusion on MR imaging can serve as a diagnostic tool in the differentiation between inflammatory processes of the lacrimal gland and lymphoma.