Primary malignant melanoma of the biliary tract: A case report and literature review

Abstract

BACKGROUND Primary malignant melanoma of the biliary tract (MBT) is a rare condition whose diagnosis requires excluding a primary origin in another location. This paper reviews the most important characteristics of MBT cases published in the literature and reports a new case. The patient reported here is the first case of primary malignant melanoma of the biliary tract with pulmonary metastasis treated with immunotherapy. This patient remains disease-free 36 mo after the treatment of metastatic lung lesions. CASE SUMMARY A 51-year-old man was admitted to the gastrointestinal department to study obstructive jaundice of a 1 wk clinical course. Magnetic resonance cholangiopancreatography revealed dilatation of the intrahepatic biliary tract and stenosis of the common hepatic duct. Given the suspicion of biliary tract neoplasia, cholecystectomy and resection of the common hepatic duct were performed with hepatic jejunostomy free of complications. Anatomo-pathological diagnosis was melanoma. After intervention, the patient was referred to the Department of Medical Oncology, where a primary origin was excluded in the skin, mucosa, and eyes. This confirmed diagnosis of primary biliary tract melanoma. Computed tomography was performed 12 mo after the procedure revealed several subcentimetric lung nodules. Wedge resection was performed. After confirming the diagnosis of pulmonary metastasis of primary melanoma of the biliary tract, the patient was started on immunotherapy with nivolumab. Tolerance to treatment was excellent. The patient remains disease-free 36 mo after the treatment of metastatic lung lesions. CONCLUSION The patient reported here is the first case of primary malignant melanoma of the biliary tract with lung metastases successfully treated with immunotherapy.

Biliary tract melanoma metastasis mimicking hilar cholangiocarcinoma: a case report

“…However, the presence of benign and malignant melanocytic populations has been demonstrated even in endoderm-derived tissues such as the gallbladder and biliary tract [ 9 ]. It can primarily affect tissues such as skin, uvea and mucous membranes, with great risk of dissemination, both through hematogenous and lymphatic system [ 3 , 4 ].…”

“…Metastases to the gallbladder and biliary tract tend to be pigmented, flat and multiple [ 15 ]. When primary, biliary tract MM still presents uncertain prognosis due to the low number of cases [ 3 ]. To differentiate between metastasis and primary biliary tract MM, the following criteria must be present: single solitary lesion, absence of previous melanoma, absence of melanoma in other sites, polypoid or papillary form and presence of biliary obstructive symptoms.…”

“…The most common primary site is the skin, but in 1.3% of cases it originates from the mucous membranes of the respiratory tract, genitourinary and gastrointestinal tracts [ 2 ]. It is a multifactorial disease requiring both genetic susceptibility and environmental exposure [ 3 ].…”

“…Metastasis to the digestive tract (DT) occurs in only 2 to 4% of cases [ 2 , 3 , 6 ]. The most common site of metastasis in the DT is the small intestine (75%) followed by the colon (25%), liver (20%) and stomach (16%) [ 7 ].…”

“…The most common site of metastasis in the DT is the small intestine (75%) followed by the colon (25%), liver (20%) and stomach (16%) [ 7 ]. The metastatic spread to the biliary system is a rare event with few reports in the literature [ 3 , 8 ]. Metastasectomy is indicated only if R0 resection is possible with acceptable morbidity [ 2 , 6 ].…”