Actinomyces in Crohn's-like appendicitis

Area of Science:

• Gastroenterology
• Pathology
• Infectious Diseases

Background:

• Appendicitis with Crohn's-like histology often suggests Crohn's disease or Yersinia infection.
• Actinomyces infection is a known cause of chronic appendicitis that can histologically resemble Crohn's disease.

Purpose of the Study:

• To investigate Actinomyces as a cause of appendicitis with Crohn's-like histological features.
• To differentiate Actinomyces-associated appendicitis from Crohn's disease.

Main Methods:

• Retrospective analysis of 20 cases of appendicitis with Crohn's-like histological features.
• Review of patient presentations, imaging studies, and histological findings.
• Follow-up assessment for development of Crohn's disease.

Main Results:

• Actinomyces was identified as the cause in 20 cases of appendicitis with Crohn's-like features.
• Most patients presented with abdominal pain; imaging suggested a mass in five cases.
• Histological findings included fibrosis and granulomas in seven cases; no patients developed Crohn's disease during a median 37-month follow-up.

Conclusions:

• Actinomyces can present as Crohn's-like appendicitis, characterized by fibrosis, transmural inflammation, lymphoid hyperplasia, and granulomas.
• Histological features of Actinomyces appendicitis can mimic Crohn's disease.
• Actinomyces infection is a distinct entity from Crohn's disease in these cases.