Background: Colonic diverticular disease is rare in developing nations but common in Western and industrialized societies. Many studies show that heart and lung transplantation increase the risk of having severe diverticulitis, although the exact magnitude of this risk remain unclear because many of these studies have been small with short follow up.
The term malignant diverticulitis has been employed to describe an extreme form of colon diverticulitis that is characterized by an extensive phlegmon and inflammatory reaction extending below the peritoneal reflection, with a tendency toward obstruction and fistula formation.
Case Report: We report a 57-year-old male, transplanted in our Institute for dilated cardiomyopathy due to previous myocardial ischemia, in whom, during the post-transplantation period, a malignant diverticulitis requiring an aggressive surgical approach was diagnosed, the diagnosis of diverticulosis was made during a colonoscopy in a pre-transplant work-up.
Conclusions: Immunosuppressed patients should be considered at high risk for developing a complicated malignant diverticular disease, and when diagnosed in a pre-transplant work-up, should be managed aggressively in terms of surgical approach when symptoms and signs suggest a diverticulitis.

Keywords: colonic diverticular disease, Heart Transplantation, dilated cardiomyopathy