A 60-year-old man presents to the emergency department with abdominal pain, chills, and constipation. Laboratory tests revealed an elevated white blood cell (WBC) count of 17,830/µL and C-reactive protein (CRP) at 188 mg/L, indicating a possible intra-abdominal infection. A CT scan revealed a 6.5 x 9.5 x 6.5 cm, peripherally well-vascularized solid mass with centrally cystic/necrotic areas, as well as the Torricelli-Bernoulli sign, originating from a small intestine segment at the level of the pelvic inlet. The pneumoperitoneum is present in the abdominal region, predominantly around the mass. The patient was evaluated as having a perforation secondary to a malignant intestinal process and was taken for laparotomy. A jejunal mass is detected 100 cm distal to the Treitz ligament, and segmental jejunal resection and anastomosis are performed.

Histopathological examination revealed mostly spindle cells and occasionally epithelial in appearance with hypercellular features and a nodular pattern. Immunohistochemical studies revealed diffuse DOG-1, CD117, and Caldesmon; CD34 and Bcl-2 were focal positive. The defined mass is diagnosed as a GIST and categorized as high risk according to the Miettinen classification/modified-Fletcher classification. The patient then undergoes a CT scan for metastasis screening, and no metastases are found. The patient is started on imatinib treatment.