Etymed
gastrointestinal stromal tumor
Definition
A mesenchymal neoplasm of the gastrointestinal tract arising from the interstitial cells of Cajal or their precursors, characterized by KIT (CD117) or PDGFRA mutations. GISTs most commonly occur in the stomach and small intestine.
Clinical context
A 58-year-old male presents with melena and iron deficiency anemia (hemoglobin 8.2 g/dL). Upper endoscopy reveals a 4 cm submucosal mass in the gastric body with central ulceration. CT abdomen shows a well-circumscribed, enhancing mass without evidence of metastasis. Endoscopic ultrasound-guided biopsy demonstrates spindle cells positive for CD117 (c-KIT) and DOG1 on immunohistochemistry. He undergoes surgical wedge resection. Molecular testing reveals a KIT exon 11 mutation. Given the tumor size and mitotic rate of 6/50 HPF (intermediate risk), adjuvant imatinib therapy is initiated.
Mnemonic
GIST = GI + Stromal + Tumor. The stroma is the supportive framework — GISTs arise from the interstitial cells of Cajal (the GI pacemaker cells). Remember: CD117 (c-KIT) positive is the hallmark.
These morphemes also unlock…
- gastr/o — stomach
- intestin/o — intestine (from intestinum, inner)
- -al — pertaining to
- strom/a — bed; mattress; supporting framework
- -al — pertaining to
- tumor — swelling; mass