Non-Hodgkin Lymphoma

A heterogeneous group of lymphoid malignancies (B-cell >> T/NK cell) that presents as nodal and/or extranodal disease; imaging pattern reflects aggressive vs indolent biology.

Big buckets

• Aggressive (high-grade): rapidly enlarging, bulky masses; may have necrosis (esp. very high-grade or post-treatment).
  • Examples: DLBCL, Burkitt lymphoma, Lymphoblastic lymphoma
• Indolent (low-grade): slow growing lymphadenopathy, organomegaly; aggressive transformation can occur in long standing cases.
  • Examples: Follicular lymphoma, Marginal zone lymphoma

Imaging patterns

Nodes

• Enlarged, usually homogeneous soft tissue; can be bulky/confluent.
• Tends to encase vessels/structures rather than invade early (helpful vs many carcinomas).

Extranodal

Common and high-yield sites. Parenchymal involvement without nodal disease can happens.

• GI: segmental wall thickening/mass; small bowel may show “aneurysmal” dilatation; perforation risk (esp. after treatment).
• Spleen/liver: diffuse enlargement ± focal lesions.
• Kidney: multiple bilateral hypoenhancing masses or diffuse infiltration; often with retroperitoneal nodes.
• Bone marrow: focal/diffuse infiltration (MRI/DWI helpful).
• CNS/Testis: sanctuary sites → consider in relapse patterns.

PET-CT

• Key for staging + response in FDG-avid NHL (many are, but avidity varies by subtype/grade).
• Residual mass ≠ active disease → metabolic assessment helps.