Purpose: Primary extranodal lymphomas of the orbit and sinonasal region are rare and occur almost only as Non-Hodgkin lymphoma (NHL). The purpose of this study was to determine the frequency of different subtypes of NHL in these regions and to describe their radiological features.
Materials and methods: Between January 2005 and January 2010, 567 patients with malignant immunoproliferative diseases (MID) were treated at our institution. Primary sinonasal and orbital manifestation was diagnosed in 36 cases. There were 13 women and 23 men with a median age of 67 years. CT and MRI were performed in 14 and 24 patients, respectively. Imaging was re-interpretated and histological subtypes were listed.
Results: Among all MID primary sinonasal and orbital NHL occurred with a frequency of 6%. Diffuse large cell lymphoma was identified in 11 cases (30%), marginal cell lymphoma in 6 (16%), and extranodal plasmacytoma in 5 (14%). Other subtypes were rare. On CT, lesions of soft tissue attenuation with homogeneous moderate contrast enhancement were seen in all cases. On T2-weighted fat saturated images 52% of the lesions were slightly hyperintense in comparison to unaffected musculature, 41% were isointense, and 7% slightly hypointense. On T1-weighted sequences most lesions (81%) were homogeneously isointense. After contrast administration marked enhancement was seen in 41%, moderate in 52%, and slight enhancement in 7%.
Conclusion: The identified radiological features should be included in the differential analysis of lesions in the orbital and sinonasal regions, but they are not specific enough. For exact therapeutic planning histopathological diagnosis of the subtype is required.
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