Metastatic malignant melanoma of the gallbladder presenting as biliary colic: a case report and review of literature.

Malignant melanoma (MM) is the most common cancer to metastasize to the gastrointestinal tract. Autopsy reports estimate that up to 15 per cent of these patients also have gallbladder metastases, and MM accounts for up to 60 per cent of metastatic lesions to the gallbladder. However, despite its prevalence, MM to the gallbladder is reported only sparingly in the literature. This discordance may be explained by the fact that these lesions are seldom symptomatic. Abdominal ultrasound remains the modality of choice in studying gallbladder pathology and has the ability to define metastatic lesions. The effect of screening for gallbladder metastases on improving survival is not well defined, and thus its role remains controversial. Cholecystectomy for melanoma metastases to the gallbladder seems to be mostly palliative, although there have been isolated reports of excellent long-term survival outcomes. The role for immunotherapy and chemotherapy in this population is not well defined, and overall prognosis is poor. Recent reports have advocated laparoscopic cholecystectomy as the treatment of choice, though there remains a concern for peritoneal port site seeding. We present the case of a 48-year-old man with MM metastatic to the gallbladder and a brief review of the literature.