Gastrointestinal stromal tumor (gross pathology)

Case Discussion

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Photograph by Ed Uthman, MD. Public domain. Posted 22 Aug 01

The lesion was first noted by upper GI endoscopy, which showed a deep bleeding ulcer thought to represent a vascular malformation. At laparotomy, examination of the external surface of the stomach showed this oblong tumor that extended from the gastric wall superiorly to the surface of the liver, to which the tumor was stuck. The surgeon dissected the tumor off the liver and included a uniform rim of normal hepatic tissue to obtain a clear margin. He also made sure to include a circumferential skirt of normal gastric wall with the resection.The diagnosis of gastrointestinal stromal tumor was made intraoperatively by frozen section. With this information, and with pathologic evaluation to assess margins, the surgeon was able to avoid doing a total gastrectomy. On permanent section, the tumor showed uniform, wispy spindle cells with no mitotic activity. Although one can't be sure even a bland GIST won't recur, the rate of recurrence is low in gastric tumors with low mitotic counts.

Published experience has shown that adherence of the tumor to the liver is not an adverse prognostic influence. On the other hand, a tumor size greater than 5 cm has negative prognostic implications. Because of their unpredictable behavior, all GIST cases need to be followed indefinitely. Surgical resection of metastases can be beneficial, and now the availability of STI571 (Gleevec), a specific inhibitor of the tyrosine kinase produced by the GIST's mutant c-kit proto-oncogene, means that recurrences can be treated with specific chemotherapy. 

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