1. What is the most likely diagnosis for a patient presenting with abdominal pain, postprandial vomiting, and weight loss, with a mass in the region between the duodenum and the pancreas and a cyst in the duodenal wall on imaging. Microscopically, the lesion shows dilated ducts and a chronic fibroinflammatory process involving the duodenal submucosa and muscular wall, extending into the adjacent pancreatic tissue?