Primary extra-gastrointestinal stromal tumor of the gallbladder: A case report.

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract, predominantly arising in the stomach (approximately 60%) and small intestine (approximately 30%), and accounting for 1%-3% of all gastrointestinal malignancies. In most cases, GISTs originate within the gastrointestinal tract; However, in rare instances, they may develop in extra-GISTs (EGISTs). Among these, gallbladder-derived EGISTs are exceedingly uncommon, with only nine cases reported to date.

CASE SUMMARY: We present the case of a 66-year-old woman who presented with recurrent right upper quadrant abdominal pain and subsequently underwent cholecystectomy. Histopathological examination with immunohistochemistry revealed CD117(+), DOG-1(+), and CD34(+), with no evidence of a primary gastrointestinal lesion, thereby confirming the diagnosis of primary gallbladder EGIST. According to the 2017 Chinese consensus on GISTs, based on the modified NIH 2008 criteria, the tumor was classified as very low risk. Consequently, the patient did not receive adjuvant targeted therapy such as imatinib, and the patient remained disease-free during a 6-month follow up.

CONCLUSION

Primary gallbladder EGISTs are exceedingly rare, with insidious onset and nonspecific clinical manifestations. Histopathological examination combined with immunohistochemistry remains the cornerstone of definitive diagnosis.