LAUSR

Surgery is the primary treatment option for patients with localized or potentially resectable gastrointestinal stromal tumours (GISTs). However, for initially unresectable GISTs with multiple metastases, there is no treatment consensus. Patients with these extremely advanced GISTs usually have a poor prognosis. We report on a successful combination therapy of a large ileal GIST with extensive metastases in the abdominal cavity. After a 55-month follow-up, no local recurrence or distant metastasis was found. This study was approved by the Ethical Committee of Tianjin Medical University Cancer Institute and Hospital. A 42-year-old man was admitted to our hospital with the chief complaint of abdominal pain. An abdominal and pelvic computed tomography (CT) scan showed a large tumour in the right abdomen and multiple metastatic tumours in the mesentery and the greater omentum: the primary tumour surrounded the small intestine, measured 13.6 × 11.8 cm, was supplied by the superior mesenteric artery and had inhomogeneous enhancement during the arterial phase (Fig. 1a–c). The CT scan also revealed a small amount of ascitic fluid and several low-density lesions in the left lobe of the liver without contrast enhancement. Fine-needle aspiration (FNA) biopsy demonstrated spindle-shaped cells (Fig. 2a,b). The tumour cells were positive for CD117, Dog-1 and CD34 (Fig. 2d–f), and negative for smooth muscle actin and S-100. The FNA biopsy specimens were too small to be evaluated for the mitotic count in 50 high-power fields. Sequencing analysis of the genomic DNA revealed a Val559Asp mutation in exon 11 of the KIT gene (Fig. 3a). The tumour was diagnosed as a GIST, possibly originating in the small intestine, with extensive metastases in the abdominal cavity. After the multidisciplinary team discussion, preoperative therapy with imatinib mesylate (IM) (400 mg/day) was initiated. After 10, 17 and 24 months of continuous IM treatment, CT scans showed that the primary tumour shrank to 5.1 × 4.7, 3.1 × 2.6 and 2.7 × 2.0 cm, respectively (Fig. 1d–f), and the ascitic fluid and metastatic tumours were apparently reduced. There was no obvious change in the size and number of liver lesions. The patient underwent a cytoreductive surgery after the 24-month preoperative IM therapy. Surgical exploration showed that the primary tumour originated in the ileum and multiple nodular tumours were visible in the greater omentum and the ileal