DDIT3 and Wilson disease: MLPS accounts for approximately 30% of LPSs and is clinically and pathologically distinct from WD/DDLPS.2 Over 90% of MLPSs contain a pathognomonic t(12;16)(q13;p11) translocation that results in expression of the FUS-DDIT3 fusion protein, whereas a smaller proportion carries EWSR1-DDIT3 gene fusions.17 Microscopically, MLPS has small, round-to-oval, nonadipocytic mesenchymal tumor cells alongside a variable number of immature lipoblasts on a background of prominent myxoid stroma (Fig 2D).