Actinomycosis of the colon with invasion of the abdominal wall: An uncommon presentation of a colonic tumour.

Actinomycosis is an uncommon chronic suppurative infectious disease that is caused by Actinomycetes organisms, which are gram-positive, microaerophilic, anaerobic bacteria. The most common type causing disease in humans is Actinomyces israelii. This organism is a commensal of the human mouth and is seldom pathogenic. When it does cause disease, however, three main clinical types of involvement are recognized including cervico-facial, thoracic and abdominal actinomycosis.Herein, we present the case of a 79-year-old male patient who underwent surgical exploration following presentation with abdominal pain and an abdominal mass, initially thought to be a malignancy. Pathologic examination confirmed this as a case of abdominal actinomycosis. This diagnosis should always be included in the differential diagnosis of patients who present with an infiltrative abdominal mass.