TSC1 and nasal cavity and paranasal sinus carcinoma: A locus-specific loss of heterozygosity in the PEComa but not in the sinonasal carcinoma was identified, suggesting the causative role of the splice mutation in the PEComa pathogenesis, because we excluded known pathogenetic pathways characteristic to PEComas (<i>TSC1/2</i>, <i>TFE3</i>, <i>RAD51B</i>).