1. Electronic Image of the Month
Colonic Actinomycosis Mimicking a Fish Bone–Related Granuloma
YUN–CHENG HSIEH,*,‡ YU–YAO CHANG,§,ʈ and KUEI–CHUAN LEE*,‡
*Division of Gastroenterology, Department of Medicine, §Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General
Hospital, Taipei; and ‡Department of Medicine, and ʈDepartment of Surgery, National Yang-Ming University School of Medicine, Taipei, Taiwan
A 78-year-old woman visited the gastroenterology clinic for
right lower-quadrant abdominal pain of 3 days’ duration.
The pain was persistent and cramping in nature, but without
Laparotomy was performed under a preoperative diagnosis of
fish bone–related small-bowel perforation with foreign body
granuloma. An encapsulated, yellowish, extraluminal tumor
associated fever, chills, nausea, vomiting, or change in bowel 6 ϫ 3.5 cm in size in the middle transverse colon was found
habit. (Figure C), but the colon mucosa was intact (Figure D). Radical
Physical examination revealed localized right lower-quadrant transverse colectomy with end-to-end anastomosis was per-
abdominal tenderness with mild muscle guarding. White blood formed. Microscopically, there was acute and chronic inflam-
cell count was 6500/mm3, hemoglobin level was 11.6 g/dL, and mation, fibrosis, and microabscess formation in sections of the
platelet count was 191,000/mm3. Her C-reactive protein level subserosal mass. Sulfur granules characterized by Splendore–
was 0.87 mg/dL, but serum alanine aminotransferase, alkaline Hoeppli phenomenon were also identified in the H&E stain
phosphatase, and carcinoembryonic antigen levels were all
(Figure E), and filamentous bacteria were shown by Gram stain
within normal range.
(Figure F) and Grocott’s methenamine silver stain (Figure G).
Abdominal sonography revealed a heterogeneous echogenic
These findings were compatible with actinomycosis. There was
lesion about 3 cm in size in the right middle abdomen, associ-
ated with a fish bone–like structure within the lesion (Figure A, no fish bone found in the specimen. The patient received
arrows).
Abdominal computed tomography scan revealed an oval- Conflicts of interest
shaped soft-tissue mass, about 38 ϫ 20 ϫ 22 mm in size, with The authors disclose no conflicts.
interior linear-shaped hyperdensity and adjacent localized ill- © 2012 by the AGA Institute
defined infiltrates in the small-bowel mesentery and focal irreg- 1542-3565/$36.00
ularity of the ileum (Figure B, arrows). http://dx.doi.org/10.1016/j.cgh.2012.06.028
CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2012;10:e81– e82

2. e82 IMAGE OF THE MONTH CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Vol. 10, No. 10
intravenous penicillin for 1 month after surgery and was dis- wall thickening and regional mass lesions adjacent to the in-
charged with oral penicillin. volved bowel with extensive infiltration.2 Radiographic findings
Actinomycosis is an unusual disease that mainly involves the and clinical symptoms are nonspecific, and the diagnosis usu-
cervicofacial area (50%) and the abdomen (20%) and thorax ally is made postoperatively.2
(15%–20%).1 In abdominal actinomycosis, the appendix and
ileocecal regions are affected most commonly. Actinomyces are References
normal inhabitants of the oral cavity and gastrointestinal tract, 1. Wong VK, Turmezei TD, Weston VC. Actinomycosis. BMJ 2011;
with opportunistic infection occurring when the mucosal bar- 343:d6099.
rier is broken.1 Abdominal actinomycosis has been associated 2. Lee IJ, Ha HK, Park CM, et al. Abdomino-pelvic actinomycosis in-
with abdominal surgery, bowel perforation, or trauma. The volving the gastrointestinal tract: CT features. Radiology 2001;220:
typical manifestations of computed tomography scan are bowel 76 – 80.