Case report: actinomycosis of the appendix--an unusual cause of acute appendicitis in children.

Abdominal actinomycosis in children is a rare disease, which is occasionally found on histologic examination after an operation for acute appendicitis. Because of its nonspecific clinical and radiological signs and symptoms and low prevalence, the diagnosis is hardly ever made before the patient undergoes an operation and tissue is available for pathologic evaluation. When the diagnosis is made, the patient should be treated with the appropriate long-term antibiotics. With antibiotic therapy, the prognosis is favorable. We describe a 13-year-old girl who presented with acute appendicitis and was found to have abdominal actinomycosis after undergoing open appendectomy, which was treated successfully with penicillin and piperacillin-tazobactam.