Orbital Lymphoma; A search for MRI predictors of disease extent and treatment response

Abstract

Background/aims: Lymphoma is the most common orbital malignancy in adults. We aimed to investigate pretreatment MRI predictors of systemic involvement and early therapy response. Material and Method: Histopathologically confirmed orbital lymphoma patients with MRI scans at the time of diagnosis and after treatment constituted the study group. Involvement of lacrimal gland, intraconal and extraconal fat, eyelid, optic nerve and/or optic nerve sheath, extraocular muscles, intraocular involvement and presence of bone destruction were evaluated from pretreatment MR scans by two radiologists. Measurements of ADC values of the mass and pons were collected and the ratio (rADC= lymphoma ADC/ pontine ADC) was calculated. Response to treatment was evaluated from the follow-up MR images. Results: Twenty patients (F/M= 10/10, mean age 57.3 ± 19.7) constituted the study group and histopathologic diagnosis was predominantly B cell lymphoma, extranodal marginal zone lymphoma being the most common (n=12, 60%). The most commonly involved structures were extraconal fat tissue (70%), lacrimal gland (50%) extraocular muscles (40%). Intraconal fat involvement was significantly higher (p=0.017) in patients with systemic disease compared to localized disease. rADC values showed no difference between patients with systemic and localized disease or patients with complete or partial response (p>0.05). Conclusion: Intraconal fat involvement of orbital lymphoma could predict a systemic disease. The predictive value of pretreatment ADC levels should be searched in larger future cohorts.