Background A 13-year-old boy was referred urgently to our gastroenterology clinic by his GP with a history of 8 weeks cramping abdominal pain, alternating diarrhoea and constipation, intermittent vomiting and a 5Kg weight loss. A brief inpatient admission resulting in commencing Movicol for constipation had no effect. An ultrasound done by the GP showed grossly inflamed bowel and was suggestive of Crohn’s disease. All bloods were normal, but the faecal calprotectin was marginally raised at 98mg/g. When he was seen in our outpatient clinic a mass was felt in the right iliac fossa. Endoscopy was arranged the following day and revealed an ulcerated, hard, voluminous mass in the caecum causing obstruction of the bowel lumen. The rest of the colonoscopy and upper GI endoscopy were macroscopically normal.

MRI demonstrated a large exophytic annular mass involving the terminal ileum and extending approximately 18cm. This was strongly suggestive of lymphoma. There were no other lesions identified on MRI. Initial histology from endoscopic biopsies showed granulation tissue reaction, diffuse neovascularisation with acute and chronic inflammatory cells. There was no evidence of dysplasia, adenocarcinoma or lymphoma. Fortunately, the mass could be entirely resected via surgery. Histology confirmed the suspicion of Non-Hodgkin’s Lymphoma in the terminal ileum.

Discussion Small bowel cancer is extremely rare in children, and it is estimated that primary gastrointestinal malignancy accounts for less than 5% of all paediatric tumours, with one study suggesting as low as 1.2%. Malignancies include lymphoma (54–74%), carcinoid (3.4–16%), carcinoma (5.5–10%) and sarcoma (3.6%). Benign differentials include inflammatory masses, polyps, haemangiomas and neurofibromas. Non-Hodgkin’s lymphoma is the commonest small bowel malignancy found in children with a high percentage of Burkitt’s lymphoma. Lymphomas are most frequently found in the terminal ileum and ileocaecal area in children. Presentation varies from palpable abdominal masses, symptoms of obstruction or abdominal pain from perforation. Treatment is a combination of surgery, chemotherapy and radiotherapy. Complete resection, as it was fortunately possible for our patient, improves the outcome significantly.

Conclusion Small bowel malignancy is a rare but critical diagnosis in children. Presentation can be insidious and can easily be mistaken as functional in nature or as a symptom of possible inflammatory bowel disease. A history of weight loss, as in this case, is vital and should promote early investigation with endoscopy. Early detection and intervention with surgery improves survival and therefore, although rare, malignancy should remain on the clinician’s differential diagnosis list until excluded.