Figure 4. A 78-year-old man with diffuse B cell lymphoma and co-existing mesenteric panniculitis (MP). A fused PET/CT image shows typical findings of MP, including inhomogeneous fatty density mass with well-defined nodules of soft-tissue density, confined by a pseudocapsule (arrows), without ¹⁸F-FDG uptake. The findings remain stable on a F/U PET/CT, 5 months later, with no clinical evidence of active lymphoma.