A 75-year-old man presents to his physician for routine follow-up. He has no complaints, other than fatigue. He has a history of hypertension, hyperlipidemia, and type 2 diabetes, all of which are well managed pharmacologically. The patient also has a history of mantle cell lymphoma (MCL), which was diagnosed at age 67 at an advanced stage. At the time, he received first-line treatment with bendamustine + rituximab and maintenance therapy with rituximab for 3 years. He has been in remission for 5 years.

Physical exam reveals generalized lymphadenopathy in the cervical and axial nodes. The patient appears pale and tired. His vitals are normal, and there is no obvious evidence of hepatomegaly on palpation, but clear evidence of splenomegaly. Routine laboratory tests (complete blood count with differential, liver function tests) are within normal range; however, PET reveals multiple sites of nodal involvement as well as confirmation of splenic involvement with marked splenomegaly, mild diffusely increased splenic ¹⁸F-fluorodeoxyglucose uptake and several high uptake splenic foci. The patient's performance status score is 0.