Case Presentation: A 24 year old male with history of malignant melanoma diagnosed five years prior presented to the emergency department with two weeks of abdominal pain. He had presented to an outside hospital one and a half weeks earlier with the same complaint and was found to have elevated pancreatic enzymes, with a lipase >3000. At that time he admitted to drinking 5-7 beers per week and he was diagnosed with alcoholic pancreatitis. CT scan of the abdomen was notable for a central mesenteric mass and suspected metastatic lesions in the omentum and retroperitoneum. He was treated and discharged from the outside hospital five days after admission.

He presented to this hospital one week later with continuing abdominal pain, nausea and anorexia and was found to have a lipase of 772. CT scan of the abdomen was remarkable for a lobulated mass at the head of the pancreas, with additional masses noted in the small bowel mesentery and retroperitoneal fat.

The patient was first diagnosed with melanoma in 2011 with a T2a 1.1mm lesion excised on his right neck. There was no lymphatic invasion and no adjuvant therapy was recommended. In early 2013, a small painless swelling on his right neck was found to be recurrent melanoma with 1 of 28 excised lymph nodes positive for metastatic disease. A subsequent sampling of 32 more lymph nodes revealed no further disease. He was treated with radiation and chemotherapy. He remained disease-free at regular follow-up visits until the above presentation.

Discussion: Acute pancreatitis is a common cause of abdominal pain and is characterized by epigastric pain and elevated pancreatic enzymes. The inciting factor in two-thirds of cases is obstructing gallstones or alcohol abuse. Other less common causes include hypertriglyceridemia, drug or toxin exposure and post-ERCP complications. Here we describe the case of a young man who was initially diagnosed with alcoholic pancreatitis but later found to have metastatic melanoma to the pancreas.  Metastases to the pancreas are rare, accounting for approximately 2% of pancreatic neoplasms. Reviews suggest that melanoma is an uncommon primary source of pancreatic metastasis, accounting for less than 20% of these rare neoplasms. Furthermore, metastases-induced acute pancreatitis (MIAP) is very uncommon and only a handful of case reports have discussed this rare manifestation of cancer. No reports of MIAP secondary to melanoma were found in the literature. 

Conclusions: Melanoma has been shown to have a unique ability among cancers to metastasize to virtually any tissue in the body.  In a patient with history of malignant melanoma, the presentation of acute pancreatitis should prompt consideration of metastatic disease as a possible etiology. Furthermore, this case illustrates the fallacy of anchoring bias, in that this patient’s diagnosis was delayed due to the assumption that his disease was caused by alcoholism despite his insistence that he drank only occasionally.