Actinomycosis mimicking colonic neoplasia

Abstract

Actinomycosis is a rare inflammatory disease caused by Actinomyces israelii. It can mimic many other diseases, such as malignant neoplasms or inflammatory bowel disease. We present a case in which actinomycosis simulated a colonic neoplasia.

Abdominal Actinomycosis misdiagnosed as liposarcoma

“…4,5,7,[10][11][12] The most frequently affected gastrointestinal sites are the appendix, cecum, and colon, but any part of the gastrointestinal tract can be involved. [4][5][6] The disease is distributed worldwide, involves all ages, and males seem to be more frequently affected than females, at a ratio of 3:1. 5,8 Currently, Abdominal actinomycosis (AA) is a challenging diagnosis as it is a rare disease with a varying and nonspecific clinical presentation that may mimic other more common entities such as colorectal carcinoma or other malignant tumors, Crohn's disease, appendicitis, diverticulitis, ulcerative colitis, pelvic inflammatory disease and intestinal tuberculosis.…”

“…5,8 Currently, Abdominal actinomycosis (AA) is a challenging diagnosis as it is a rare disease with a varying and nonspecific clinical presentation that may mimic other more common entities such as colorectal carcinoma or other malignant tumors, Crohn's disease, appendicitis, diverticulitis, ulcerative colitis, pelvic inflammatory disease and intestinal tuberculosis. 4,6,7 The diagnosis of AA is frequently made in surgical specimens, when surgery is undertaken in the pursuit of neoplasia or appendicitis. Less than 10% of the cases are diagnosed before surgery.…”

“…The presence of sulfur granules on microbiologic or histological examination, though important, is not pathognomonic. [4][5][6][7][8][9][10] The most important CT finding is a large mass adjacent to the involved bowel. In the rectosigmoid junction, cystic masses are more common, whereas in the transverse or ascending colon purely solid masses are the predominant finding.…”

“…It takes, at least, a week for the growth in anaerobic incubation media, and the sulfur granules are found in only 50% of the specimens. [4][5][6]9,10,13 The microscopic finding of the isolated Actinomyces in the culture media is a gram-positive, nonacid-fast, thin, branching filaments.…”

“…The disease usually occurs in immunocompetent persons but may afflict those with diminished host defenses, though. [4][5][6][7][8] The local tissue damage caused by trauma, recent surgery, irradiation, and loss of mucosal integrity by foreign bodies, perforated appendix or diverticulitis, neoplasia is recognized as predisposing factors. 4,5,[7][8][9][10] However, cases were reported without any preceding mucosal injury.…”