In this case, the clinico-radiological picture suggested a pancreatic pseudocyst/gastric GIST, but intraoperative frozen section and final histopathology confirmed the diagnosis of a malignant epithelioid cystic GIST (high grade as per the modified NIH GIST grading system), with IHC markers showing positivity for CD117 while CD34, Desmin, and DOG-1 were negative, making the case atypical [18,19]. This evidence concerns the gene ANO1 and gastrointestinal stromal tumor.