Primary malignant melanoma of gallbladder.

Gallbladder primary malignant melanoma (GPMM) is a rare and controversial entity. The existing controversy on the subject appears mainly because of the lack of definitive objective criteria of primitivity. Objective criteria proposed by the specific literature for distinguishing GPMM from secondary gallbladder melanoma include the exclusion of previous primitive melanoma, absence of synchronous involment of other sites, the unicity of lesion, its polipoid or papilary shape and the presence of a junctional melanocitary component. After laparoscopic cholecystectomy in one of our patients, dark polypus inside the gallbladder was found. A malignant melanoma was diagnosed according to all five criteria for GPMM.