Clinical differentiation of non-Hodgkin orbital lymphoma and idiopathic orbital inflammation

Purpose : Non-Hodgkin orbital lymphoma (NHOL) and idiopathic orbital inflammation (IOI) can be difficult to differentiate due to overlapping clinical, radiological and laboratory features. Additionally, orbital biopsies are not always possible for deep localizations. Differentiation is necessary for adequate and timely treatment. In this retrospective study, we investigate the potential of clinical discriminating features within these diseases and we aim to develop a set of clinical features that can be used as a simple differentiating tool in the diagnosis of NHOL and IOI. Methods : We retrospectively investigated clinical features of 234 adult patients diagnosed with NHOL or IOI between 2000 and 2017 in the University Medical Center Utrecht. We statistically analyzed clinical patient- and disease characteristics using a multivariable logistic regression. A set of discriminating features was tested for correct classification using a receiver operator characteristic curve. Results : We included 82 patients with NHOL and 152 patients with IOI in this study. Age of disease onset, the presence of pain, eyelid edema, ptosis and proptosis showed statistically significant differences between NHOL and IOI (all p<0.01), with a combined classification power (area under the curve) of more than 90% (p<0.01). Conclusions : Clinical features are important in the diagnostic process of NHOL and IOI. Using a set of simple features including age, presence of pain, diplopia, eyelid edema, ptosis and proptosis, a differentiation between NHOL and IOI can be made with high accuracy. A multicenter replication is needed to validate these results.