World J Gastrointest Surg. 2009 November 30; 1(1): 62-64.
Published online 2009 November 30. doi: 10.4240/wjgs.v1.i1.62.
Actinomycosis of the sigmoid colon: A case report
Antonio Privitera, Charanjit Singh Milkhu, Vivek Datta, Manuel Rodriguez-Justo, Alastair Windsor and Charles Richard Cohen.
Antonio Privitera, Charanjit Singh Milkhu, Vivek Datta, Alastair Windsor, Charles Richard Cohen, Department of Surgery, University College London Hospitals, London NW1 2BU, United Kingdom
Manuel Rodriguez-Justo, Histopathology Department, Royal Free & University College Medical School, Rockefeller Building, London WC1E 6JJ, United Kingdom
Author contributions: All authors have participated in the perioperative treatment of the patient, diagnosis and follow-up.
Correspondence to: Dr. Antonio Privitera, MD, PhD, MRCS, Department of Surgery, University College London Hospitals, London NW1 2BU, United Kingdom.
Telephone: +44-759-5423060 Fax: +44-120-6742030
Received July 15, 2009; Revised September 15, 2009; Accepted September 22, 2009;
Abdominal actinomycosis is a chronic suppurative infection caused by Actinomyces species. The ileo-cecal region is most commonly affected, while the left side of the colon is more rarely involved. The infection has a tendency to infiltrate adjacent tissues and is therefore rarely confined to a single organ. Presentation may vary from non specific symptoms and signs to an acute abdomen. A computed tomography scan is helpful in identifying the inflammatory process and the organs involved. It also allows visual guidance for percutaneous drainage of abscesses, thus aiding diagnosis. Culture is difficult because of the anaerobic character and slow growth of actinomycetes. Colonoscopy is usually normal, but may shows signs of external compression. Preoperative diagnosis is rare and is established only in less than 10% of cases. In uncomplicated disease, high dose antibiotic therapy is the mainstay of treatment. Surgery is often performed because of a difficulty in diagnosis. Surgery and antibiotics are required in the case of complicated disease. Combined medical and surgical treatment achieves a cure in about 90% of cases. The authors report a case of sigmoid actinomycosis where diagnosis was made from the histology, and a review of the literature is presented.
Keywords: Abdominal pain, Actinomycosis, Gram-positive bacteria, Sigmoid colon, Sulfur
Actinomycosis is a chronic suppurative infection which spreads to contiguous tissues and has the tendency to form external sinuses that may drain characteristic sulfur granules composed of a matrix of calcium phosphate, colonies of actinomycetes, cellular debris and associated organisms[ 1]. The most common pathogen in humans is Actinomyces Israelii, named after Israel who was first to describe the microorganism in a human autopsy specimen[ 2]. This is a gram-positive, non-spore forming anaerobic bacterium which is a commensal in the mucosa of the oral cavity and upper gastrointestinal tract, but able to cause opportunistic infections[ 1].
Cervicofacial actinomycosis is the most common clinical form, comprising up to 60% of cases. Abdominal actinomycosis is rare and reported only in about 20% of cases[ 3].
The authors report a case of actinomycosis of the sigmoid colon and review the literature.
A 67-year-old African-Caribbean lady presented with a 3-mo history of altered bowel habits associated with worsening right iliac fossa pain and nausea. Past medical history showed hypertension, depression and a left-sided stroke. Her surgical history revealed a cesarean section at the age of 25. On examination she was dehydrated, pyrexic (38.2° C) and tachycardic (118 beats/min). The abdomen was tender with guarding in the right iliac fossa, and obstructive bowel sounds were heard. Blood tests showed a microcytic anemia (hemoglobin 9.3 g/dL) and a high white cell count (20 000/mm 3). A rapid sickle cell test performed prior to the procedure was negative.
A computed tomography (CT) scan of the abdomen and pelvis was performed and this showed a 6.5 cm × 7.7 cm inflammatory mass in the right iliac fossa involving the sigmoid colon which contained a few diverticulae. No free air was noted. The patient was resuscitated, transfused with 2 units of blood and was commenced on broad spectrum antibiotics. At laparotomy, an abscessed mass of the sigmoid colon was found. This involved a loop of small bowel and infiltration of the uterus, fallopian tubes and ovaries. A Hartmann’ s procedure was carried out (Figure 1). Histology showed an inflammatory mass with abscess formation arising from outside the bowel with the mucosa being well defined and unremarkable. The bowel wall was fibrotic and edematous with a few diverticulae, but no evidence of perforation. Numerous lymphoid aggregates, some with reactive germinal centers were present within the submucosa. Extensive pericolic necrosis containing numerous bacterial colonies of Actinomyces species were noted (Figures 2 and 3). A diagnosis of sigmoid actinomycosis was made. The patient made an uneventful recovery and was started on a 6-mo course of penicillin. At 1-year follow-up she was well and free from disease.
Figure 1
Figure 1
Figure 1
Surgical specimen: Sigmoid colon mass (80 mm × 30 mm) with abscess formation.
Figure 2
Figure 2
Figure 2
Histology: A colony of Actinomyces is seen within the pericolonic inflammatory tissue.
Figure 3
Figure 3
Figure 3
Gram-positive staining of an Actinomyces colony.