GPNMB and neoplasm with perivascular epithelioid cell differentiation: tRCC and PEComas have highly overlapping epithelioid morphologies and immunophenotypes, including expression of melanocytic lineage genes and lysosomal markers (PMEL, MelanA, Cathepsin K, GPNMB) that are canonical MiT/TFE transcriptional targets4–6.