Genetic analysis of intraoral KIT-positive gastrointestinal stromal tumor (GIST).

Gastrointestinal stromal tumors (GISTs), mesenchymal neoplasms originating from the cells of Cajal, usually appear in the gastrointestinal tract and abdomen. They often mimic other lesions, including smooth muscle cell tumors and neurogenic tumors. This study presents a case in which a GIST appeared over a 2-month period and was treated by excision and curettage, with no sign of recurrence during the next 42 months. The study also aims to characterize the GIST. Histopathologic analysis and KIT gene amplification and sequencing were performed. On mutation analysis of the GIST material, the novel 69338Tdel mutation was found in exon 11, and the diagnosis of intraoral stromal tumor was made. GISTs in the intraoral region display pathologic properties similar to others developed throughout the gastrointestinal system. Diagnosis is the first step of treatment for a patient. The discovery of oncogenic KIT mutations in GISTs has led to the development of targeted molecular therapy using tyrosine kinase inhibitors. This study investigates the histopathologic and molecular diagnostics of GISTs, and, to the authors' knowledge, it represents the first genetic study of a GIST developing in the intraoral region.