Primary malignant melanoma of the common bile duct - A case report and review of the literature

Primary malignant melanoma of the common bile duct is rare. To our knowledg e, only 6 cases have been reported previously. The pathologic diagnosis of primary malignant melanoma in extracutaneous sites often requires the use o f confirmatory immunohistochemical stains and electron microscopy studies, as well as tests to rule out other possible remote or concurrent primary si tes. The presence of junctional activity adjacent to the tumor is another i mportant requisite for the diagnosis of this entity. Nevertheless, absolute exclusion of a metastatic melanoma from an unknown occult site or regresse d site is not entirely possible. We describe our observations in a case of primary malignant melanoma of the common bile duct in a 48-year-old man and discuss the criteria for diagnosis of primary melanoma.