Abdominal actinomycosis mimicking acute appendicitis.

Area of Science:

• Medical Microbiology
• Surgical Pathology
• Abdominal Imaging

Background:

• Acute appendicitis is a common cause of acute abdominal pain, typically presenting in the right lower quadrant.
• Abdominal actinomycosis is a rare bacterial infection that can mimic other intra-abdominal pathologies, including appendicitis and malignancy.
• Diagnostic challenges arise due to the nonspecific presentation of actinomycosis.

Observation:

• A 52-year-old woman presented with acute right lower quadrant abdominal pain, initially diagnosed as acute appendicitis based on clinical and CT findings.
• Intraoperative findings during laparoscopic appendectomy raised suspicion for malignancy due to a firm cecum.
• Subsequent open laparotomy and right hemicolectomy revealed an ileocecal mass confirmed as actinomycosis, not malignancy.

Findings:

• Pathological examination confirmed abdominal actinomycosis, a rare bacterial infection, as the cause of the ileocecal mass.
• The patient received 10 days of intravenous antibiotics and was discharged with a diagnosis of abdominal actinomycosis.
• Initial clinical and radiological features strongly suggested acute appendicitis, highlighting a potential diagnostic pitfall.

Implications:

• Abdominal actinomycosis should be considered in the differential diagnosis for patients presenting with right lower quadrant pain, especially when imaging is suggestive of appendicitis or malignancy.
• Early recognition and appropriate antibiotic treatment can potentially avoid extensive surgical intervention for abdominal actinomycosis.
• This case underscores the importance of considering uncommon infectious etiologies in abdominal pain presentations that mimic more common surgical conditions.