An 82-year-old man had his third episode of melanotic stool. Two previ
ous workups had failed to localize the source of bleeding. A Tc-99m la
beled RBC scan visualized the gallbladder early in the study. Administ
ration of sincalide visually decreased the activity, confirming gallbl
adder activity. Three months later, at his second surgery, hepatic met
astases were finally identified as the source of bleeding. In retrospe
ct, the hepatic activity is inhomogeneous with at least two cold defec
ts that could have represented hepatic metastases.