Objective: In this pictorial essay, we described the clinical, pathologic, and computed tomographic (CT) findings of malignant gastrointestinal stromal tumors (MGISTs) and attempt to establish the correlation between radiologic appearance and malignant potential. Methods: This retrospective analysis included 20 patients receiving treatment for MGIST between 2008 and 2010. The diagnosis was established by pathology and immunohistochemistry. All these patients underwent preoperative CT. Clinical presentation, pathology and CT images were analyzed. Helical CT images were reviewed for morphologic features such as tumor size, number and location, tumor margins, necrosis, degree of enhancement and metastasis. Results: Gastrointestinal bleeding, abdominal pain and discomfort, and without clinical symptom were common findings and were observed in 9 (45%), 6 (30%), and 5 (25%) of the 20 patients. 8 (40%) tumors were located in stomach, and 10 (50%), 1 (5%) and 1 (5%) were located in small intestine, mesentery and peritoneum, respectively. Male to female ratio was about 1:2. The size of MGIST ranged from 2.6 cm to 17.5 cm with a mean of 8.7 cm. All tumors density was inhomogeneous and heterogeneous enhancement. MGISTs with highly malignant located in small intestine were about 30% higher than stomach. The “satellite” tumours were found in 6 cases with high malignant risk. 7 cases were suffered from liver metastasis, and 4 cases went with seeding into the abdominal cavity, 1 cases went with lymph node metastasis. Histologically, 19 cases (95%) were of spindle cell type. Immunohistochemical stains demonstrated a strong positivity for both c-kit (CD117) and CD34s enhancement in 19 (95%). Conclusion: Clinical expression is varied in MGIST patients. Female might be predominance in MGIST. The GISTs located in small intestine would tend to be more aggressive. The satellite tumours, necrosis and cystic degeneration were strongly benefit for MGIST diagnosis. Furthermore, intestinal obstruction doesn’t support the diagnosis. Lymph node metastasis and calcification is rare. Objective: In this pictorial essay, we described the clinical, pathologic, and computed tomographic (CT) findings of malignant gastrointestinal stromal tumors (MGISTs) and attempt to establish the correlation between radiologic appearance and malignant potential. Methods: This retrospective analysis included 20 patients receiving treatment for MGIST between 2008 and 2010. The diagnosis was established by pathology and immunohistochemistry. All these patients underwent preoperative CT. Clinical presentation, pathology and CT images were analyzed. Helical CT images were reviewed for morphologic features such as tumor size, number and Location: tumor margins, necrosis, degree of enhancement and metastasis. Results: Gastrointestinal bleeding, abdominal pain and discomfort, and without clinical symptom were common findings and were observed in 9 (45%), 6 (30%), and 5 % of the 20 patients. 8 (40%) tumors were located in stomach, and 10 (50%), 1 Male to female ratio was 1: 2. The size of MGIST ranged from 2.6 cm to 17.5 cm with a mean of 8.7 cm. All tumors were highly heterogeneous and heterogeneous enhancement. MGISTs with highly malignant located in small intestine were about 30% higher than stomach. The “satellite ” tumors were found in 6 cases with high malignant risk. 7 cases were suffered from liver metastasis, and 4 cases went with seeding into the abdominal cavity, 1 cases went Immunohistochemical stains demonstrated a strong positivity for both c-kit (CD117) and CD34s enhancement in 19 (95%). Conclusion: Clinical expression is varied in The GISTs located in small intestine would tend to be more aggressive. The satellite tumors, necrosis and cystic degeneration were strongly benefit for MGIST diagnosis. Furthermore, intestinalobstruction does not support the diagnosis. Lymph node metastasis and calcification is rare.