CASE 15153 Published on 18.10.2017

Pelvic actinomycosis

Section

Genital (female) imaging

Case Type

Clinical Cases

Authors

Mariana Lima, Ana Luísa Lourenço, Isabel Oliveira, Ana Cardoso

Department of Radiology, Centro Hospitalar de Lisboa Central - Hospital de Santo António dos Capuchos; Alameda de Santo António dos Capuchos, 1169-050 Lisbon, Portugal; Email: mariana_talina@hotmail.com
Patient

50 years, female

Categories
Area of Interest Pelvis ; Imaging Technique CT, MR
Clinical History
A 50-year-old female patient went to the emergency department with complaints of an increase in the frequency of defecation (more than ten times per day), without presence of blood or pus. She reported constant pain in the left lower quadrant, asthenia, anorexia and weight loss (ten pounds) during the past four weeks.
Imaging Findings
An abdominopelvic CT (Computed Tomography) was performed, which demonstrated a mass in the left iliac fossa, in the region of the left adnexa. It showed a heterogeneous enhancement following intravenous contrast, with cystic/necrotic areas. This mass was locally infiltrative and extended to the sigmoid colon, which showed parietal thickening and hyperenhancement. An intra-uterine device (IUD) was visualised. Left mild hydronephrosis was present, with the ureter dilated upstream to the mass described and showing a “stop” in that region. The thickness of the renal parenchyma was preserved.
Because of the suspicion of a possible ovarian tumour, the patient underwent MR (Magnetic Resonance) in the following days, which confirmed the presence of a heterogeneous mass, with central areas of T2-hyperintensity, corresponding to cystic/necrotic components. With this technique, also a thickening of the sigmoid colon wall that appeared adherent to the tumour was visualised, as well as stranding of the surrounding fat.
Discussion
In the presence of a mass located in the region of the left adnexa and signs/symptoms typical for a malignant disease, such as heavy weight loss, asthenia and anorexia, the patient underwent surgery. A total hysterectomy with bilateral salpingo-oophorectomy and a Hartmann's procedure were performed. Pre-operatively, bilateral renal stents were placed because of hydronephrosis. The histopathological analysis revealed inflammatory changes associated with Actinomyces.
Actinomycosis is a chronic suppurative infection that is caused by Actinomyces species [1], which are gram-positive anaerobic bacteria commonly present in the human body, namely in the oropharynx and bowel [2]. Abdominopelvic actinomycosis can present as fistula, sinus, inflammatory pseudo-tumour, abscess formation and dense fibrosis [1, 3]. Pelvic actinomycosis is associated with the use of IUDs [1]. In fact, in 25% of women, IUDs become infected by Actinomyces, although only 2%-4% of them suffer from serious actinomycotic infections [4]. The clinical presentation is usually indolent [5] and the most commonly involved organs are ovary and fallopian tube. However, it can also spread to the uterus, urinary bladder, rectal area, urachus, abdominal wall and peritoneum [1].
The most common findings on CT are the presence of an abscess or mass with heterogeneous contrast enhancement and associated bowel wall thickening [4]. The lesions are usually very infiltrative and show extension across tissue planes [6]. As the disease progresses, it can produce a frozen pelvis that resembles pelvic malignancy or endometriosis [1]. On MR imaging, the actinomycotic mass may show cystic spaces with high signal intensity on T2-weighted images [5]. Because of the presence of abundant fibrotic tissue, the remaining inflammatory stranding usually demonstrates intermediate-to-low signal intensity on T2-weighted images [1].
Removal of the IUD is fundamental in patients with actinomycosis. Although open surgical resection makes possible a definite diagnosis and facilitates the cure, the first line of treatment is antibiotic therapy with intravenous high doses of beta-lactam, followed by oral therapy for two to six months [7]. The prognosis is good, and even in the presence of extensive infection, combined surgical and antibiotic therapy can establish the cure in the majority of cases.
Our patient remained asymptomatic after surgery and adequate antibiotic therapy.
The principal message we would like to transmit is that when a woman with an IUD presents with a pelvic mass that is locally infiltrative and associated to insidious clinical symptoms and laboratory data are suggestive of an infection, pelvic actinomycosis should be suspected.
Differential Diagnosis List
Pelvic actinomycosis
Left ovarian cancer
Left ovarian metastasis
Gastrointestinal stromal tumour (GIST) of the sigmoid colon
Pelvic inflammatory disease with a tubo-ovarian abscess
Endometriosis
Inflammatory bowel disease with abscess formation
Diverticulitis with abscess
Final Diagnosis
Pelvic actinomycosis
Case information
URL: https://eurorad.org/case/15153
DOI: 10.1594/EURORAD/CASE.15153
ISSN: 1563-4086
License