18FDG-PET at 1-Month Intervals Is a Better Predictive Marker for GISTs That Are Difficult to Be Diagnosed Histopathologically : A Case Report

Abstract EN

Imatinib mesylate is a tyrosine kinase inhibitor of c-KIT and PDGFRA.

Imatinib mesylate is an effective drug that can be used as a first-choice agent for treatment of GISTs.

Prior to treatment, molecular diagnosis of c-KIT or PDGFRA is necessary; however, in some types of GISTs, it is impossible to obtain a sufficient amount of specimen for diagnosis.

An inoperable or marginally resectable GIST in a 79-year-old female was difficult to be diagnosed at a molecular pathological level, and hence, exploratory treatment was initiated using imatinib combined with 18FDG-PET evaluation at 1-month intervals.

PET imaging indicated a positive response, and so we continued imatinib treatment in an NAC setting for 4 months.

As a result, curative resection of the entire tumor was successfully performed with organ preservation and minimally invasive surgery.

18FDG-PET evaluation at 1-month intervals is beneficial for GISTs that are difficult to be diagnosed histopathologically.