Primary GLI1-altered mesenchymal tumor in the kidney with PTCH1-GLI1 gene fusion: case report and literature review

GLI1 -altered mesenchymal tumor is a recently characterized entity defined by genetic alterations in the GLI1 gene, including fusions and amplifications. Although these tumors have been reported in various anatomical sites, only five cases have so far been documented in the kidney. Among these renal cases, FOXO4 was identified as the GLI1 fusion partner in four tumors, while the fusion partner remains unidentified in the remaining case. Here, we report the first case of a primary renal GLI1 -altered mesenchymal tumor involving PTCH1 as the fusion partner in a 56-year-old female. We detail its clinicopathological and molecular features, along with follow-up information. Furthermore, we review the clinicopathological and molecular profiles of all six reported renal GLI1 -altered mesenchymal tumors (including the current case) and summarize the characteristics of all 11 reported mesenchymal tumors with PTCH1-GLI1 fusion across various anatomical locations. This case expands the spectrum of GLI1 fusion partners in primary renal GLI1 -altered mesenchymal tumors and broadens the known anatomical distribution of these tumors.