Arterial Pseudoaneurysm Mimicking a Mural Nodule Within a Pancreatic Cyst

Pancreatic cysts with high-risk characteristics are at increased risk of harboring high-grade dysplasia or pancreatic cancer. Endoscopic ultrasound may clarify the nature of the cystic lesion and its malignant potential. A mural nodule found through endoscopic ultrasound within a cyst may represent malignancy and require fine-needle aspiration. Pancreatic pseudocysts are benign walled-off fluid collections that form in the setting of pancreatitis and may be difficult to differentiate from neoplastic cysts. Pseudoaneurysms form when pancreatitis inflammation damages vessel walls and can cause fatal hemorrhage. We present a pancreatic pseudocyst with pseudoaneurysm mimicking a neoplastic cyst with a mural nodule.