What are the CT and MRI features of retroperitoneal lymphoma?
Retroperitoneal lymphadenopathy or enhancing soft tissue masses, whether infiltrative or well-circumscribed, are seen, typically with homogeneous soft tissue attenuation, low-intermediate signal intensity on T1-weighted images, and high signal intensity relative to skeletal muscle.
Central necrosis or calcification may be present, but most often after treatment, and low signal intensity on T2-weighted images after treatment may indicate nonviable tumor or fibrosis.
When there is confluent lymphadenopathy sandwiching the mesenteric vessels, this is sometimes referred to as the “sandwich” sign.
Whereas Hodgkin’s lymphoma tends to spread to contiguous lymph node stations, non-Hodgkin’s lymphoma is more likely to involve a variety of nodal groups and extranodal sites.