Even low-risk gastrointestinal stromal tumors (GIST) can produce metastasis after surgical resection and require long-term follow-up, according to a recently published study in Surgical Case Reports.

Currently, the standard of care for low-risk GISTs is surgical resection; however, neither optimal margins nor optimal surgical procedure is yet defined. According to some reports, recurrence after surgical resection occurs in about 40% of cases, with either local recurrence or metastasis.

Very low-grade tumors have little mitotic activity and a tumor size smaller than 2 cm, according to the Fletcher classification. Recurrence of very low-risk tumors is rare, as indicated by a recurrence rate of only 2% approximately. Follow-up is recommended every 6 months for 5 years.


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The case involved a 57-year-old woman who initially presented with an episode of melena. Although an initial physical exam was unremarkable, a blood workup revelated moderate anemia. Attending physicians ordered computer tomography (CT) imaging which revealed a high signal intensity in the descending duodenum. An endoscopic study showed a bleeding submucosal tumor; because of the risk of bleeding, a fine needle aspiration was not performed at that point.

The tumor was surgically removed per wedge resection. The resected tumor measures 16×12 mm pathology. Immunohistochemistry analysis revealed it to be a low-risk GIST according to the fletcher classification and no-risk according to the Miettinen classification. 

Follow-up included endoscopic ultrasonography every 3 months and CT every 6 months. Two years after surgical resection, CT revealed two hyperechoic lesions of 10 mm and 25 mm, respectively, in the liver. There was no change in tumor markers or local recurrence in the duodenum. After magnetic resonance imaging, both tumors were classified as GIST metastases. 

The patient was started on treatment with imatinib, and at the moment of the presentation of the case (2 months after diagnosis), the patient remains asymptomatic and is doing well.

“Besides the size, mitotic activity, and location of the tumor, several other factors are also related to the malignant potential of GISTs,” the authors wrote. “ Therefore, even a small duodenal GIST with low mitotic activity can never be considered as entirely benign, and long-term follow-up is still important.”

Reference

Mita J, Tada K, Kuboyama Y, et al. Liver metastases 2 years after resection of a very-low-risk duodenal gastrointestinal stromal tumor: a case report. Surg case rep. Published online October 10, 2022. doi:10.1186/s40792-022-01551-1