The Role of Neoadjuvant Therapy in a Giant Gastric Gastrointestinal Stromal Tumour: A Case Report and Review of the Literature.

Gastric gastrointestinal stromal tumour (GIST) is a rare disease with an annual incidence of 10 cases per million. Herein, we present the case of a 45-year-old man who visited our clinic with complaints of weight loss and anorexia, without changes in bowel habits or vomiting, for four months. On physical examination, all vital signs were normal. The abdomen was distended without tenderness and had a giant upper abdominal mass. Tumour marker investigation revealed high levels of cancer antigen 125 with normal levels of alpha-1-fetoprotein, carcinoembryonic antigen, and carbohydrate antigen. A computed tomography (CT) scan showed a mass measuring 35 × 25 × 20 cm, likely originating from the fundus of the stomach. Upper gastrointestinal endoscopy indicated external compression of the stomach and a fundal submucosal mass. Ultrasound-guided biopsy demonstrated the presence of a GIST. There was a severe danger of both the tumour rupturing during surgery and the combined excision of adjacent organs if the surgery was performed with the massive tumour. Therefore, daily neoadjuvant therapy with imatinib 400 mg was administered for three months. Post-therapeutic CT indicated a significant reduction in the size of the mass, which now measured 17 × 14 × 21 cm. The patient underwent surgical resection a month after the completion of neoadjuvant therapy, and the post-operative period was uneventful. He was followed up regularly at the general surgery department for 24 months without recurrence. This case asserts the benefit of neoadjuvant therapy in reducing the tumour size pre-operatively, which enhances the complete resection rate, prevents the need for multi-organ resection, and lowers the risk of surgery.