We report a case of gastrointestinal stromal tumor (GIST) of the jejunum, observing its growth.
A 65-year-old man admitted for a solid mass in the left lower abdomen was found in abdominal computed tomography (CT) to have a solid 9.0cm tumor in the left lower abdomen. Since no mass was shown in the same CT slice taken 20 months ago, doubling time for this tumor appeared to be about 70 days. Under a diagnosis of a mesenchymal tumor of the small bowel, we conducted partial resection of the jejunum including of the tumor. H-E staining showed dense fasicular proliferation of spindle-shaped tumor cells in bundles and many nuclear divisions in a single field. Immunohistochemical studies showed that tumor cells were positive for c-KIT protein and CD34 but negative for other markers. This tumor was diagnosed as uncommitted malignant GIST considered high-grade malignancy with aggressive proliferation.
Surgical resection of the tumor is the principal treatment for GIST, but new drugs highly effective against GIST have been developed. To ensure appropriate surgical procedure and optimal indications of new drugs, we must understand the unique biology of GIST clarified by more clinicopathological studies.