Interestingly, our customized lymphoma panel revealed genetic polymorphisms in 2 different genes (ATM M1134L, variant allelic frequency (VAF) 52%, and KMT2C S2869C, VAF 55%) as well as one pathogenic TET2 mutation (R1452*, VAF 19%) and two NOTCH2 variants of uncertain significance (VUS), S2403C and S2389P, with a VAF 7% each, and turned out being most likely an early follicular colonization by a splenic diffuse red pulp small B cell lymphoma (SDRPL) that the patient developed in the follow-up. The gene discussed is KMT2C; the disease is lymphoma.