Background: Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors of the gastrointestinal tract localized mostly in the upper or medial part of the digestion tract.
Case: A colonic GIST in a young woman extended to the pelvis, giving the impression of an ovarian tumor.
Conclusion: In the case of a pelvic mass, especially if other unusual anamnestic data and signs are present, the possibility of other than a gynecologic tumor has to be considered. Every effort should be made to identify the origin of the tumor and related anatomic structures, especially the ovaries.