Next-generation sequencing (NGS) analysis using a panel of 26 genes designed for peripheral T-cell lymphomas (ARID1A, ATM, BCOR, CARD11, CCR4, CD28, CTNNB1, DDX3X, DNMT3A, FYN, IDH2, IRF4, JAK1, JAK3, KMT2D, PIK3CD, PLCG1, PRKCB, RHOA, SETD2, STAT3, STAT5B, TET2, TNFRSF1B, TP53, VAV1) disclosed a mutation involving the exon 4 of the DNMT3A gene (c.178-9C>T) with a variant allele fraction (VAF) of 46%, also described in the general population at a very low frequency and interpreted as a constitutional variant. The gene discussed is DNMT3A; the disease is peripheral T-cell lymphoma, not otherwise specified.