TSC1 and neoplasm with perivascular epithelioid cell differentiation: The presence of the TFE3 fusion protein probably substitutes MiTF in these PEComas, explaining the absence of MiTF expression and the lower expression of Melan A. TFE3 rearrangements and TSC1/2 alterations were, for a long time, considered to be mutually exclusive [10], but recently a case of TCS1-mutated PEComa displaying a TFE3-altered phenotype was reported, challenging this conclusion [112].