| Summary points: | A 41-year-old woman presents with a 2-month history of continuous watery diarrhoea. Previous treatment, abdominal examination, abdominal ultrasonography computed tomography, resection, and histology, which showed diffuse large B-cell-type of malignant lymphoma with serous invasion, are described. The authors discuss a case of primary malignant lymphoma of the ileum presenting as intussusception. |