Primary malignant melanoma of the gallbladder, metastatic to the common bile duct.

A primary malignant melanoma of the gallbladder, metastatic to the common bile duct, is reported. Both tumor sites were first visualized by abdominal sonography. The presence of the common bile duct metastasis was confirmed by endoscopic retrograde cholangiopancreatography. Histologic evidence is presented that the primary tumor did arise in the gallbladder and that the metastasis to the common bile duct most likely occurred as a consequence of mucosal implants from tumor cells that were shed in the bile.