Metastatic Common Bile Duct Melanoma Presenting as Obstructive Jaundice: A Case Report and Review

Abstract Introduction/Objective Malignant melanomas (MM) account for 4-7% of all new cancer cases. The most common primary site is the skin, however, in 1.3% of cases, these tumors originate from the mucous membranes of the respiratory, genitourinary, and gastrointestinal tracts. The metastatic spread to the biliary system is extremely infrequent, with rare reports in the literature. Herein, we report a case of history of cutaneous MM with metastasis to the biliary tract. Methods/Case Report A 35-year-old Caucasian female presented with pruritis, dark urine, and jaundice. Laboratory results favored the cholestatic process (total bilirubin – 10 mg/dL, alkaline phosphatase – 500 U/L, AST- 400 U/L, ALT – 1000 U/L). She had a remote diagnosis of MM of the left chest with metastases to bilateral axillary and periclavicular lymph nodes 8 years ago. She underwent wide local excision of the skin lesion and lymph node dissection then. ERCP with direct cholangioscopy revealed a 3 x 2 cm obstructive mass in the common bile duct which was biopsied to reveal cohesive, pleomorphic, epithelioid cells containing black-brown pigment with enlarged, irregular, and hyperchromatic nuclei. These atypical cells stained strongly with SOX10 and Mart-1 immunohistochemical stains, confirming the diagnosis of metastatic malignant melanoma. Results (if a Case Study enter NA) NA. Conclusion MM is cancer that originates from melanocytes, derived from the neural crest during embryogenesis. The pathogenesis of metastatic spread to the biliary system is still unknown due to the paucity of literature describing this. Diagnosis is often difficult, with many patients completely asymptomatic or occasionally presenting with biliary symptoms. There should be a detailed history, and extensive clinical workup along with extensive histological and immunoprofile, esp. in cases with a history of cutaneous melanoma for early detection of a potential metastasis leading to adequate management.