GLI1-Altered Soft Tissue Tumor

**Semantic type:** Neoplastic Process

**Definition:** A rare mesenchymal neoplasm of uncertain histogenesis that arises from soft tissue and viscera. It is characterized by the presence of nests and sheets of neoplastic epithelioid cells separated by a rich delicate arborizing vascular network, and GLI1 gene rearrangement. It presents as a slow-growing painless mass. The majority of cases have an indolent clinical course following complete excision. Distant metastases have been reported in a minority of cases.

**Synonyms:** - Epithelioid Neoplasm with GLI1 Rearrangement - GAESTT - GLI1-Altered Epithelioid Soft Tissue Tumor - Pericytoma with t(7;12)