Appendiceal Tumor or Something More?

Abstract

Question: A 66-year-old woman with an unremarkable medical history was referred for a colonoscopy by her general practitioner with a 4-month history of abdominal persistent pain at right lower quadrant, 4 out of 10 intensity, with no irradiation, and no relieving or worsening factors. She denied fever, diarrhea, anorexia, weight loss, or other symptoms. The colonoscopy showed a subepithelial protrusion to the lumen in the region of the appendiceal orifice with a whitish liquid material discharge (Figure A). Biopsies were not representative for submucosal tissue, showing unspecific alterations as edema, congestive vessels, hemorrhagic foci, and polymorphic cell infiltration, and were negative for malignancy. Laboratory data were normal, including carcinoembryonic antigen and CA19.9 levels. Abdominal-pelvic computed tomography showed small appendicoliths (Figure B) with no other alterations. After multidisciplinary discussion and owing to diagnostic uncertainty, the decision was made to undertake a surgical approach. The patient underwent a laparoscopic right hemicolectomy. Pathologic examination (Figure C, D) of the surgical specimen revealed the diagnosis. What is the diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Pathologic analysis of surgical specimen showed bacteria colonies with sulfur granules compatible with Actinomyces surrounded by a polymorphic cell infiltrate and mucosal erosion. The appendix showed fibrosis with no neoplastic lesions. The patient remains asymptomatic after 1 year of follow-up. Actinomycosis is rare and has a worldwide distribution. Actinomyces israelii is the most common human pathogen.1Gómez-Torres G.A. Ortega-Gárcia O.S. Gutierrez-López E.G. A rare case of subacute appendicitis, actinomycosis as the final pathology reports: a case report and literature review.Int J Surg Case Rep. 2017; 36: 46-49Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar These organisms are indigenous in the oral cavity, gastrointestinal tract, and genital tract, with opportunistic infection occurring when the mucosal barrier is broken. Actinomycosis commonly occurs in three distinct forms: cervicofacial (55%), abdominopelvic (20%), and thoracic (15%).2Lee S. Kwon H. Cho J. et al.Actinomycosis of the appendix mimicking appendiceal tumor: a case report.World J Gastroenterol. 2010; 16: 395-397Crossref PubMed Scopus (21) Google Scholar The abdominopelvic form involves the appendix and caecum in 66% of the presentations.1Gómez-Torres G.A. Ortega-Gárcia O.S. Gutierrez-López E.G. A rare case of subacute appendicitis, actinomycosis as the final pathology reports: a case report and literature review.Int J Surg Case Rep. 2017; 36: 46-49Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar The critical step seems to be the disruption of the mucosal barrier. Predisposing factors include previous abdominal surgery, bowel perforation, neoplasia, poor oral hygiene, and intrauterine contraceptive devices, and these insults can precede clinical presentation by several weeks to many years.3Liu K. Joseph D. Lai K. et al.Abdominal actinomycosis presenting as appendicitis : two case reports and review.J Surg Case Rep. 2016; 5: 1-3Google Scholar Its resemblance to other diseases such as appendicitis, diverticulitis, colon carcinoma, Crohn’s disease, ulcerative colitis, and tubo-ovarian abscess make the diagnosis challenging2Lee S. Kwon H. Cho J. et al.Actinomycosis of the appendix mimicking appendiceal tumor: a case report.World J Gastroenterol. 2010; 16: 395-397Crossref PubMed Scopus (21) Google Scholar and <10% of cases are diagnosed before surgery.3Liu K. Joseph D. Lai K. et al.Abdominal actinomycosis presenting as appendicitis : two case reports and review.J Surg Case Rep. 2016; 5: 1-3Google Scholar The clinical presentation has an indolent course, with an initial nonspecific presentation, usually with lower abdominal pain and fever.1Gómez-Torres G.A. Ortega-Gárcia O.S. Gutierrez-López E.G. A rare case of subacute appendicitis, actinomycosis as the final pathology reports: a case report and literature review.Int J Surg Case Rep. 2017; 36: 46-49Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Computed tomography wor magnetic resonance imaging can be useful for determining the anatomic location and extent of disease, but are nonspecific.3Liu K. Joseph D. Lai K. et al.Abdominal actinomycosis presenting as appendicitis : two case reports and review.J Surg Case Rep. 2016; 5: 1-3Google Scholar A definitive diagnosis is generally based on the histologic identification of actinomycotic granules or culture of the Actinomyces species, or both.1Gómez-Torres G.A. Ortega-Gárcia O.S. Gutierrez-López E.G. A rare case of subacute appendicitis, actinomycosis as the final pathology reports: a case report and literature review.Int J Surg Case Rep. 2017; 36: 46-49Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar When uncomplicated abdominal actinomycosis is diagnosed without surgery, medical treatment with antibiotics is indicated.1Gómez-Torres G.A. Ortega-Gárcia O.S. Gutierrez-López E.G. A rare case of subacute appendicitis, actinomycosis as the final pathology reports: a case report and literature review.Int J Surg Case Rep. 2017; 36: 46-49Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Surgery is usually reserved for bulky necrotic lesions, large abscesses, and fistulas, and to exclude malignancy.3Liu K. Joseph D. Lai K. et al.Abdominal actinomycosis presenting as appendicitis : two case reports and review.J Surg Case Rep. 2016; 5: 1-3Google Scholar In our case, no local or systemic predisposing factors were identified.