Summary

Abdominal actinomycosis is a rare disease caused by different anaerobic Actinomyces species. We report the case of a 55-year-old woman who presented with a painless, slow growing, left upper abdominal mass that developed after a laparoscopic cholecystectomy. A CT scan and MRI of the abdomen revealed a desmoid tumour of the left rectus abdominis muscle.

Surgical excision was performed with an uneventful postoperative course. The histological analysis of the specimen was inconsistent with a desmoid tumour and revealed an infection of Actinomyces israelii in the anterior abdominal wall that was confirmed with a microbiology culture. The surgical treatment was followed by a course of penicillin antibiotic therapy for 6 months. This treatment resulted in full recovery with no further complications. Although it is rare, the patient’s history of laparoscopic cholecystectomy was identified as the likely source of infection.