A 42-year-old man who was being treated for pneumonia developed severe, sudden-onset abdominal pain with features of shock and peritonism. The clinical picture combined with radiological investigations raised suspicion of a bowel perforation necessitating urgent surgical review and emergency laparotomy. This diagnosed a jejunal perforation with abnormal lymph nodes. Histological examination confirmed diffuse large B-cell lymphoma. The patient was subsequently started on a course of chemotherapy. While gastrointestinal perforation secondary to antilymphoma treatment is a well-recognised complication, primary perforation caused by the lymphoma itself must always be considered.