Pathologic complete response confirmed by surgical resection for liver metastases of gastrointestinal stromal tumor after treatment with imatinib mesylate

Figure 1 Histological study showing spindle cells with mitoses (HE, × 200) (A) and immunohistochemistry findings revealing positive staining for CD117 (B) and CD34 (× 200) (C) in primary GIST of the stomach.

Figure 2 Contrast-enhanced CT scan (A) and MRI (B) on T1-weighted image 107 mo after the initial operation.

Figure 3 Scanning view of metastatic GIST (× 15) (A), histological study revealed spindle cells with mitoses (HE, × 200) (B), immunohistochemistry findings revealed positive staining for CD117 (C) and CD34 (× 200) (D) in metastatic GIST of the liver obtained from liver biopsy.

Figure 4 MRI on T1-WI 30 mo after treatment with Imatinib (A) and contrast-enhanced CT 34 mo after the treatment with Imatinib (B). The metastatic lesions (S4 + S5) are indicated.

Figure 5 Serous and cut-surface views of resected specimen obtained from partial hepatectomy (S4 + S5) after treatment with Imatinib.

Figure 6 Histological study showing no viable tumor cells and hyaline degenerative tissues (HE, × 200) (A) and immunohistochemistry findings revealing negative staining for CD117 (× 200) (B) in the resected specimen after treatment with Imatinib.