Malignant melanoma presenting as a mass obstructing the common bile duct

Pathologic and computed tomographic correlation of an obstructing common bile duct mass, found to be malignant melanoma, is presented. No tumour was demonstrated elsewhere. Such a pattern of presentation has not previously been described in this condition. Malignant melanoma, even in the absence of disease elsewhere, should be considered in the differential diagnosis of such lesions seen on computed tomography.