Biliary tract melanoma metastasis mimicking hilar cholangiocarcinoma: a case report

A case of metastatic melanoma in the liver mimicking colorectal cancer with synchronous liver metastasis

INTRODUCTION AND IMPORTANCE

Colorectal cancer (CRC) presenting with synchronous liver metastasis is relatively common, occurring in approximately 20 % of patients1. Herein we report an atypical case of a patient who presented with a new, obstructing colon mass with synchronous liver metastasis, biopsy proven to be malignant melanoma.

CASE PRESENTATION

An 81-year-old male presented to the hospital emergency department with abdominal pain, diarrhea, and 30-pound unintentional weight loss over the past 4 months. Investigations revealed an obstructing cecal mass with multiple large, hypodense hepatic masses suspicious for metastatic disease. A multidisciplinary evaluation ensued, and the decision was made to treat with palliative intent. The patient was surgically treated with a diverting stoma and an intraoperative biopsy of the hepatic masses demonstrated metastatic melanoma. The patient did report a remote history of malignant melanoma and underwent curative-intent resection a decade earlier. There was no evidence of a new primary cutaneous melanoma. A tentative plan for checkpoint inhibitor therapy was discussed, but his medical issues worsened, and the patient died before any anti-cancer therapy could be started.

CLINICAL DISCUSSION

The clinical picture of obstructing colon mass with synchronous liver masses most commonly represents a colon primary with synchronous liver metastasis. The capacity for melanoma to mimic other pathologies is unusual but has been described, with case reports describing metastasis to the eye, biliary hilum, liver, pancreas, colon, small bowel, and brain. This case serves as a good reminder that melanoma may mimic a variety of oncologic presentations, even after a very long disease-free interval.

CONCLUSION

Our patient suspected to have metastatic colon cancer was found instead to have metastatic melanoma, with significantly different therapeutic options and prognosis.

Metastatic Melanoma Invading the Minor Duodenal Papilla in a Patient With Pancreas Divisum Causing Acute Recurrent Pancreatitis: A Case Report

Metastasis to the gastrointestinal (GI) tract should always be a consideration when melanoma, particularly metastatic disease, is diagnosed. While metastasis to the small intestine is common, given its rich blood supply, metastasis to the pancreatic ducts is extremely rare. In patients with pancreatic divisum, disease spread to the minor papilla can greatly increase the chance of developing pancreatitis due to the potential for increased pancreatic intraductal pressure. We present one unique case of metastatic melanoma to the minor duodenal papilla causing pancreatitis.

Intra-Abdominal Malignant Melanoma: Challenging Aspects of Epidemiology, Clinical and Paraclinical Diagnosis and Optimal Treatment—A Literature Review

According to European consensus-based interdisciplinary guidelines for melanoma, cutaneous melanoma (CM) is the most deadly form of dermatological malignancy, accounting for 90% of the deaths of skin cancer patients. In addition to cutaneous melanoma, mucosal melanoma occurs in four major anatomical sites, including the upper respiratory tract, the conjunctiva, the anorectal region, and the urogenital area. As this cancer type metastasizes, a classification used in the current medical literature is the distinction between secondary lesions and primary malignant melanoma of the abdominal cavity. Given that malignant melanoma is the most common cancer that spreads to the gastrointestinal tract, different imaging modalities compete to diagnose the phenomenon correctly and to measure its extension. Treatment is primarily surgery-based, supported by immunotherapy, and prolongs survival, even when performed at stage IV illness. In the end, special forms of malignant melanoma are discussed, such as melanoma of the genito-urinary tract and amelanotic/achromic melanoma. The importance of this present literature review relies on yielding and grouping consistent and relevant, updated information on the many aspects and challenges that a clinician might encounter during the diagnosis and treatment of a patient with intra-abdominal melanoma.