Brachiocephalic to left brachial vein thrombotic vasculitis accompanying mediastinal pancreatic fistula: A case report

BACKGROUND: Pancreatitis is a severe inflammatory pancreatic disease commonly due to bile duct stones or excessive alcohol usage, with clinical manifestations of abdominal pain, nausea, fever, and fluid collections. Healthy persons with less symptomatic pancreatitis are quite rare. Herein, we report a case of a patient with an undetermined onset of pancreatitis mimicking left arm cellulitis due to thrombotic vasculitis of the brachiocephalic vein. CASE SUMMARY: A 50-year-old woman visited our hospital for tenderness in the left arm over several recent days. She was diagnosed with cellulitis on the left arm due to left elbow tenderness. Intravenous antibiotics administration did not improve symptoms and laboratory data worsened; thus, chest and abdominal computed tomography (CT) was performed. CT demonstrated pancreatitis with pseudocyst around the pancreas extending to the mediastinum. Thrombotic vasculitis of the brachiocephalic to left brachial vein was observed, which could be the cause of left elbow pain. A pancreatic fistula was found in the head of the pancreas by endoscopic retrograde cholangiopancreatography, so a pancreatic cyst drainage tube via the duodenum was placed in the pseudocyst. Cyst content culture was positive for Escherichia coli infection. Clinical symptoms, imaging findings, and inflammatory reactions resolved gradually after starting therapeutic intervention. The mediastinal pancreatic pseudocysts shrunk, and the venous thrombi remained but shrunk. CONCLUSION: The case of a patient with pancreatitis with an undetermined onset that mimics left arm cellulitis is reported. Deep vein thrombosis should be kept in mind when treating patients with severe inflammatory disease.