A 20-year-old male reported abdominal pain and fullness, with no bowel opening for three weeks. The frontal X-ray was recorded (X-ray: Erect CXR). Also, the frontal view taken two years earlier is also attached (X-ray: Erect CXR, two years earlier).

What is the most likely diagnosis? (Answer is posted in the comment section below!)  This case is from the Editorial team of Docplexus and is meant for educative purposes only.