Gastrointestinal stromal tumors: A multidisciplinary challenge

Abstract

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors located in the alimentary tract. Its usual manifestation is gastrointestinal bleeding. However, small asymptomatic lesions are frequently detected as incidental finding. Characteristically, most GISTs (> 95%) are positive for the KIT protein (CD117) by IHC staining and approximately 80%-90% of GISTs carry a mutation in the c-KIT or PDGFRA genes. Mutational analysis should be performed when planning adjuvant and neoadjuvant therapy, due to its possible resistance to conventional treatment. The arise of tyrosine kinase inhibitor has supposed a revolution in GISTs treatment being useful as adjuvant, neoadjuvant or recurrence disease treatment. That is why a multidisciplinary approach to this disease is required. The correct characterization of the tumor at diagnosis (the diagnosis of recurrences and the evaluation of the response to treatment with tyrosine kinase inhibitors) is fundamental for facing these tumors and requires specialized Endoscopist, Radiologists and Nuclear Medicine Physician. Surgery is the only potentially curative treatment for suspected resectable GIST. In the case of high risk GISTs, surgery plus adjuvant Imatinib-Mesylate for 3 years is the standard treatment. Neoadjuvant imatinib-mesylate should be considered to shrink the tumor in case of locally advanced primary or recurrence disease, unresectable or potentially resectable metastasic tumors, and potentially resectable disease in complex anatomic locations to decrease the related morbidity. In the case of Metastatic GIST under Neoadjuvant treatment, when there are complete response, stable disease or limited disease progression, complete cytoreductive surgery could be a therapeutic option if feasible.

Keywords: Disease management; Endoscopy; Gastroenterology; Gastrointestinal stromal tumors; Nuclear medicine; Oncology; Pathology; Radiology; Surgery; Tyrosine kinase inhibitors.

Figure 1

Localized gastrointestinal stromal tumors on computed tomography scan. A: Gastric; B: Duodenal; C: Ileal; D: Jejunal. A and B show respectively a gastric tumor and a duodenal tumor of exophytic growth with well-defined borders. Appreciate in C the different densities inside the tumor due to due to necrosis, haemorrhage, or degenerative components. D shows a jejunal GIST in left iliac fossa.

Figure 2

Metastatic gastrointestinal stromal tumors on computed tomography scan. A: Liver metastasis; B: Peritoneal metastasis “Gistosis”. In A, it is appreciated a large hepatic metastasis in segment IV. B shows the CT of a patient with disseminated peritoneal disease “GISTosis”.

Figure 3

Rectal gastrointestinal stromal tumor on magnetic resonance.

Figure 4

Characteristic endoscopic image of gastric gastrointestinal stromal tumor.

Figure 5

Endoscopic ultrasonography images of gastrointestinal stromal tumors.

Figure 6

Gastrointestinal stromal tumors on positron emission tomography with fluorodeoxyglucose. A: Giant gastric GIST on a patient with neurofibromatosis type 1; B: Gastric GIST with an unique liver metastasis. GIST: Gastrointestinal stromal tumor.

Figure 7

Histological sections of ileal gastrointestinal stromal tumor. A: HE stain; B: Immunohistochemistry with C-KIT.

Figure 8

Management algorithm of gastrointestinal stromal tumors. GIST: Gastrointestinal stromal tumor.