Appendiceal actinomycosis can appear weeks to years after an episode of acute appendicitis with rupture.
Clinical features:
(1) history of perforated appendix, sometimes years before
(2) nonspecific abdominal symptoms (low-grade fever, anorexia, weight loss, pain)
(3) palpable right lower quadrant mass
(4) evidence of inflammation
(5) right inguinal lymphadenopathy
(6) variable fistula formation
(7) variable intestinal obstruction
The main differential diagnosis is a cecal or appendiceal tumor.
Microscopic findings:
(1) purulent exudate
(2) sulfur granules composed of Gram-positive filamentous bacteria
Positive anaerobic cultures for Actinomyces species.
