Question
A 66-year-old man with decompensated alcoholic cirrhosis presented with abdominal pain. He had a history of an appendectomy 23 years previously. He underwent endoscopic injection sclerotherapy (EIS) using N-butyl-2-cyanoacrylate (Histoacryl®) for gastric varices (GV) 1 month previously (Figure 1). Physical examination was normal. Abdominal X-ray revealed small intestinal gas with niveau and a 3-cm, high-density structure in the pelvic cavity (Figure 2). What is the diagnosis and cause?