Actinomycosis mimicking a pelvic malignancy. A case report.

BACKGROUND: Pelvic actinomycosis is difficult to diagnose preoperatively. The chronic infection is locally infiltrative and causes a profound induration of infected tissue planes. This induration, combined with absence of fever and leukocytosis, can mimic a pelvic malignancy. CASE: A 55-year-old woman was diagnosed with a pelvic mass after a two-month history of intermittent lower abdominal pain. The patient had had an intrauterine device for 12 years; it was removed two months prior to an exploratory laparotomy for the symptomatic mass. The mass was highly suggestive of colorectal cancer, with the rectosigmoid colon indurated and adherent to the uterus and sacrum. The induration of the colon extended caudally to within 3 cm of the anal verge. An abdominoperineal resection was performed along with a total abdominal hysterectomy, bilateral salpingo-oophorectomy and colostomy. Pathology revealed acute and chronic endometritis, left tuboovarian abscess and extensive, acute inflammation of the rectosigmoid colon without evidence of diverticuli. Actinomycosis was diagnosed based on the characteristic sulphur granules seen on hemotoxylin and eosin staining.
CONCLUSION: Actinomycosis can mimic pelvic and abdominal malignancies. Surgeons should be aware of this infection to potentially spare women morbidity from excessive surgical procedures.