Giant and high-risk gastrointestinal stromal tumor in the abdomino-pelvic cavity: A case report

Gastrointestinal stromal tumors (GISTs) are benign mesenchymal tumors of the gastrointestinal tract. The clinical presentations of patients with GIST are variable and may be non-specific. The current study reports the case of a 66-year-old man that presented with a gradual enlargement of the abdomen, emaciation, hyperhidrosis and frequent and urgent micturition. A computed tomography (CT) scan of the abdomen revealed a large, heterogeneous, low density mass that occupied the entire abdomino-pelvic cavity. Magnetic resonance imaging (MRI) identified a high signal intensity on the T2 weighted image and an intermediate signal intensity on the T1 weighted image. A contrast enhanced CT scan and MRI demonstrated the uptake of contrast material. A biopsy revealed that the tumor was composed of spindle cells, and immunohistochemical analysis identified the presence of mast/stem cell growth factor receptors. Together, these results lead to a diagnosis of GIST. The clinical findings, imaging modalities and pathological studies suggested that the GIST was a large and high-risk tumor located in the abdomino-pelvic cavity. The final surgical results confirmed these findings. Following conservative treatment with imatnib (400 mg, daily) for 6 months, the tumor became smaller and was suitable for surgery, which the patient received in December 2014. The final surgery confirmed the high-risk GIST. Subsequent to the surgery, the patient was recommended to continue the use of imatnib with regular CT or MRI reexaminations every 3 months, which are planned to continue for 3 years.