Abstract Primary retroperitoneal lymphoma (PRL) is a rare entity, as retroperitoneal lymphomatous involvement usually represents secondary disease. We present four histologically confirmed cases demonstrating relatively homogeneous retroperitoneal masses, frequently encasing major vessels with preserved vascular patency and mild luminal narrowing, without vascular occlusion. Contrast-enhanced computed tomography (CT) was the main diagnostic tool, while magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) and positron emission tomography/computed tomography (PET/CT) provided complementary structural and metabolic information. Elevated LDH was a frequent finding. The consistent imaging pattern of homogeneous enhancement, vessel encasement with preserved flow, and FDG avidity strongly suggests PRL. Recognizing these features is crucial to differentiate PRL from retroperitoneal sarcomas and other neoplasms, allowing targeted biopsy and preventing unnecessary surgery. PRL should be considered in the differential diagnosis of large homogeneous retroperitoneal masses when imaging and laboratory data are concordant.
Delibaş et al. (Wed,) studied this question.