Imatinib response of gastrointestinal stromal tumor patients with germline mutation on KIT exon 13: A family report

Figure 1 Pedigree of the family shows vertical transmission of KIT exon 13 c. 1924A>G (p.Lys642Glu; p.K642E) mutation. Het: Heterozygous.

Figure 2 Electropherogram shows exon 13 c. 1924A>G missense mutation leading to a change of lysine at position 642 to glutamine (p.Lys642Glu; p.K642E) (dbSNP: 121913512) of KIT gene at heterozygote state in three affected family members.

Figure 3 Microscopic findings of gastrointestinal stromal tumor located in the proximal jejunum. Hematoxylin and Eosin staining revealed spindle cells in small bowel submucosa and wall (A). Immunohistochemistry for DOG1 (B) and c-KIT (C) showed immun activity in the tumor cell (original magnification: A, B and C, 40 ×).

Figure 4 ¹⁸F-fluorodeoxyglucose positron emission tomography-computerized tomography scans of the gastrointestinal stromal tumors recurrence. Serial ¹⁸F-FDG PET-CT scans showed submucosal, solid lesions in jejunum (SUVmax: 1.68-1.50) (A, B) and ileum (SUVmax: 4.69) (C) with maximum 2 cm in diameter, consisted with GIST recurrence on the follow-up (arrows). ¹⁸F-FDG: ¹⁸F-fluorodeoxyglucose; PET-CT: Positron emission tomography-computerized tomography; GIST: Gastrointestinal stromal tumors.

Figure 5 Imatinib response evaluation of the gastrointestinal stromal tumors using contrast-enhanced abdominal computerized tomography. Pre- and post-treatment CT images are shown on upper and lower series respectively. A partial response is seen in jejunal (A, B) and ileal (C) GISTs in the following 3 mo after imatinib therapy (arrows). CT: Computerized tomography; GIST: Gastrointestinal stromal tumors.