Metabolic pseudoprogression in a patient with metastatic KIT exon 11 GIST after 1 month of first-line imatinib: a case report

• DOI: 10.3389/fonc.2023.1310452
• Publication Date: 2023-12-20T10:48:18Z
• Authors: Elisa Tassinari; Nicole Conci; Giacomo Battisti; Francesco Porta; Valerio Di Scioscio; Maria Giulia Pirini; Dario de Biase; Maria Concetta Nigro; Miriam Iezza; Fausto Castagnetti; Luigi Lovato; Stefano Fanti; Maria Abbondanza ...; Margherita Nannini
• Keywords: PDGFRA; Stromal tumor; Targeted Therapy; Imatinib Mesylate; Fluorodeoxyglucose

Background Positron emission tomography (PET) with 18-fluorodeoxyglucose ( 18 FDG) has proven to be highly sensitive in the early assessment of tumor response gastrointestinal stromal tumors (GIST), especially cases where there is doubt or when prediction could clinically useful for patient management. As widely known, kinase mutations have an undoubtful predictive value sensitivity imatinib, and inclusion KIT PDGFRa mutational analysis diagnostic workup all GIST now considered standard practice. Case presentation Herein, we described detail a case exon 11 mutated-metastatic patient, who presented unexpected metabolic progression at FDG-PET evaluation after 1 month first-line unconfirmed liver biopsy performed near after, which conversely shown complete pathological response. Conclusions This report aims highlight existence this pseudoprogression beginning imatinib therapy order avoid treatment discontinuation. Therefore, during molecular targeted always deserves evaluated context disease profiling, discordant finding between functional imaging background, short-term longitudinal control should suggested.