Uterine doughnut in early proliferating phase: potential pitfall in gastrointestinal bleeding studies.

A 41-year-old woman with rectal bleeding was referred to our department for gastrointestinal (GI) bleeding study. She was in early post-menstrual period and had stable vital signs. A GI bleeding study with Tc-99m SC revealed uterine blush in the pelvis. The shape of activity and quick fading excluded a GI bleeding. To rule out an intermittent bleeding, patient underwent a second bleeding study with Tc-99m RBC. Serial images showed uterine "doughnut" in the pelvis. The activity neither changed in shape nor showed distal movement with time excluding a GI hemorrhage. Uterus in early proliferating phase could be a potential pitfall in GI bleeding studies.