GLI1 amplified/fused mesenchymal tumor: A case report and review of the literature.

Glioma-associated oncogene homologue 1 (GLI1) is an important transcription factor downstream of Hedgehog (HH) signaling pathway, and can be used as a marker of HH signaling pathway activation. GLI1 gene translocations have been reported in several tumor types, including those associated with t(7;12) translocated dermatocytoma, plexus fibromyxoma, and gastroblastoma and other types of malignant soft tissue tumors, whereas GLI1 amplification is actually very rare in tumors. In this case report, we describe for the first time a tumor in the right mandibular gingiva, which is consistent with GLI1 amplified/fused mesenchymal tumor. The tumor cells are elliptic, polygonal and spindle tumor cells growing into nests and segments, lobulated and occasionally mitotic. The identification of these pathological features can help guide pathologists to make appropriate diagnosis and, if necessary, follow-up molecular tests. Our case has been treated with surgical resection. To date, no recurrence or metastasis has occurred and the prognosis is good.