Metastatic malignant melanoma of the gallbladder: a case report and review of the literature.

Both primary and metastatic melanoma of the gallbladder are rare. Involvement of the gallbladder occurs in about 15% of all gastrointestinal metastatic localizations in post-mortem case records. It is often difficult to differentiate primary from metastatic lesions on the basis of clinical, radiological and histopathological features. Melanoma involving the biliary tree seldom causes relevant symptoms during life, and this is why cases reported in the literature are few and those documented in living patients even fewer. We report a case of a young woman with a metastatic gallbladder melanoma who presented with a long and vague clinical history of symptoms that mimicked chronic cholecystitis with epigastric right hypochondrial pain without instrumental evidence of disease until the development of acute cholecystitis. We report this case to emphasize the need for awareness of the possibility of gallbladder involvement in the melanoma patient and to underline the necessity of meticulous investigation of unclear lesions of the gallbladder and biliary tree in patients with a past history of malignant melanoma. The clinical presentation, diagnosis, histopathology, prognosis and treatment of primary and metastatic melanoma of the gallbladder are also discussed and reviewed.