Mutations in ALK and TSC1 in a gastrointestinal stromal tumor: a case report

Background Gastrointestinal stromal tumors rarely occur in children, but when they do, their biological behavior and histopathological patterns differ from those of adults. Case presentation A 13-year-old boy with a gastrointestinal stromal tumor was characterized by a rare genetic mutation. The patient complained of “fatigue with intermittent abdominal pain for 1 month”. According to the preoperative imaging examination, gastroscopy, and gastroscopic biopsy, the patient was diagnosed with a gastric stromal tumor. Postoperative pathology showed that the tumor cells were fusiform and ovoid, and mitotic figures were easily seen. Immunohistochemistry revealed that the tumor was S-100(+), SOX10(−), CD34(+), SMA(partially+), DOG-1(+), CD117(+), KI-67 (positive for 20% + of the subjects and 40% + of the hotspots), and SDHB(−). Genetic tests showed missense mutations in ALK and TSC1. With surgical treatment, the tumor was completely removed. The patient recovered well and was discharged on the ninth day after the operation. He is currently under follow-up. Conclusions In this case involving a patient with a gastrointestinal stromal tumor, immunohistochemistry indicated that the tumor was an "SDH-deficient type", and gene detection showed no KIT or PDGFRA mutation but rare ALK and TSC1 mutations, which adds to the knowledge of the types of gene mutations in children with gastrointestinal stromal tumors.