[A 55-year-old man with abdominal pain and fever].

A 55-year-old man was admitted for evaluation of chronic abdominal pain and fever. Computed tomography demonstrated a retroperitoneal inflammatory process involving the mesenteric root. Adipose tissue biopsy showed panniculitis mesenterica with granulomas. Further examinations confirmed the diagnosis of plasmocytoma type IgG kappa. Treatment with steroids (prednisolone), resulted in immediate improvement of pain and fever. Mesenteric panniculitis represents a paraneoplastic syndrome associated with non-Hodgkin lymphoma.