Severe abdominopelvic actinomycosis with colon perforation and hepatic involvement mimicking advanced sigmoid colon cancer with hepatic metastasis: a case study

BACKGROUND: Actinomycosis is a rare chronic invasive disease caused by Actinomyces spp. Although abdominopelvic actinomycosis, which involves the colon and the pelvic organs extensively, has been frequently reported, abdominopelvic actinomycosis presenting with colon perforation and hepatic involvement concurrently has yet to be reported. CASE PRESENTATION: A 55-year-old woman presented at the emergency room with squeezing epigastric pain. Palpation of the abdomen revealed a hard mass with no acute peritoneal signs. Vital signs were normal range except for tachycardia. Initial laboratory testing revealed leukocytosis, anemia, elevated C-reactive protein (CRP), hypoalbuminemia; and normal AST/ALT and BUN/creatinine. CT scan of the abdomen-pelvis revealed a microperforations of the sigmoid colon, abscess in the left lower quadrant and hepatic lesion. Furthermore, there was a large infiltrating conglomerated mass invading the urinary bladder, left adnexa, sigmoid, left inguinal canal and left pelvic wall area. Ultrasound revealed an intra-uterine device (IUD). All these findings initially raised a suspicion of malignancy such as advanced cancer of the colon with liver metastasis. Despite the rarity of the disease, actinomycosis were not excluded because of the IUD found on ultrasound. Parenteral antibiotics and percutaneous drainage of abdomen abscess as well as fasting with total parental nutrition were prescribed for sigmoid perforation and abscess. After 10 days of conservative treatment, no remarkable change was detected in conglomerated mass invading pelvis. Furthermore, the finding of newly developed mechanical small bowel obstruction warranted surgery. Exploratory laparotomy was performed for the removal of perforated colon, obstructive small bowel and organs involved and postoperative histology confirmed a diagnosis of colonic actinomycosis. The patient made an uneventful recovery and was started on a 6-month course of penicillin. CONCLUSIONS: Abdominopelvic actinomycosis presenting with colon perforation and hepatic involvement is extremely rare; however, it is clinically similar to advanced colon cancer with liver metastasis, therefore, complicating the preoperative diagnosis. A diagnosis of abdominopelvic actinomycosis should be considered in patients with a history of IUD and chronic abdominal pain, along with an abdominal mass or cutaneous abscess. If surgery is indicated, preoperative empirical antibiotic therapy for actinomycosis and frozen biopsy during surgery may be considered.