A 28-year-old patient has been hospitalized with complaints of abdominal pain. Objectively, the anterior abdominal wall takes part in the act of breathing. Muscle tension, tenderness, and positive signs of peritoneal irritation can be detected by palpation of the abdominal wall. Hepatic dullness is absent. Peristalsis sounds cannot be auscultated. What is the most likely diagnosis in this case?