A 30 years old known alcoholic patient presented to EMOPD with a complaint of severe pain in the abdomen. On examination, rigid abdomen is seen. Patient also had multiple episodes of pain in the abdomen for the last 4-5 years and lost 5 kg of weight in the past 6 months. Serum lipase and amylase level is normal. CECT abdomen was perfomed . What is the most likely diagnosis?