RESUMO
BACKGROUND: Actinomyces infection is a chronic inflammatory process that can sometimes, clinically and radiographically, closely mimic a malignant tumour, which may lead to giving a delayed or inappropriate treatment. CLINICAL CASE: Male 41 years old, with no previous history, with abdominal pain of one month onset, as well as weight loss, intermittent fever and diarrhoea. He developed acute abdomen and underwent surgery, finding a tumour in the distal ileum with necrosis and punctiform perforations. A resection was performed on the affected part of the ileum and colon, as well as an ileostomy using Hartmann's procedure. CONCLUSIONS: Actinomycosis is a disease that must be considered by the surgeon when faced with a clinical picture of subacute onset with intermittent fever, weight loss, abdominal pain, and even anaemia in patients with abdominal and retroperitoneal abscesses or previous history of surgery.