as other bacteria of the Actinomyces
species are saprophytes in the oral cavity, gastrointestinal, and female genital tract. The destruction of the muscular barrier by trauma, that is, endoscopic manipulation, operations, immunosuppression, and chronic inflammatory disease, is recognized as predisposing factors for penetration of Actinomyces
]. Several forms of immunosuppression, such as leukemia, lymphoma, renal insufficiency, renal transplant, and diabetes, have been demonstrated to facilitate this process [4
]. It is accepted that the risk of pelvic actinomycosis resulting from IUD use is very low. Only about 92 reported cases exist in the published English language literature, despite 30 million patient-year of IUD use [5
]. About 80% of cases of pelvic actinomycosis have been reported in women using an IUD. Actinomyces israelii
infects 1.65% to 11.6% of IUD users, and infection is more common in women who have had an IUD use in situ longer than four years [6
Our patient had a 3-year history of IUD which had recently been removed. The IUD may be considered the initial trigger of abdominalpelvic actinomycosis. Ileocecal region and appendix itself are the most frequently involved regions. Recognized causes of infection are appendicitis, diverticulitis, inflammatory bowel disease, and previous open and laparoscopic surgery. Endoscopic procedures have been also described as rare potential causes. No previous surgery or history of inflammatory diseases of the abdomen were reported by our patient.
Clinical symptoms are usually not specific and include a wide range of clinical presentation. Acute abdomen can be observed when complications such as perforation or fistulization occur; more frequently, as in our case, abdominal pain is present.
Preoperative diagnosis of pelvic abdominal actinomycosis can be difficult because of the insidious nature of the infection. Biochemical and haematological investigations are almost not specific. Usually, diagnosis with fine-needle aspiration cytology is in impossible pre-operatively. In fact the filaments and sulfur granules of Actinomyces are surrounded by extensive inflammatory tissue that is the sample site of fine-needle aspiration cytology. In our case these procedures were conclusive of inflammatory lesion.
Preoperative radiologic diagnosis is rarely performed. Ha et al. [7
] analyzed the CT findings of ten patients with abdominal actinomycosis. The aggressive nature of invasion and infiltration of contiguous tissues and organs, such as the large intestine, greater omentum, or abdominal wall, was remarkable and comparable to that seen in acute necrotizing pancreatitis. Lee et al. [8
] have examined CT scans in 18 patients with pathologically proved abdominalpelvic actinomycosis involving the gastrointestinal tract. Eight patients had a history of using IUDs. The sigmoid colon was most commonly involved (50%). All patients showed concentric (n
= 15) or eccentric (n
= 3) bowel wall thickening, with a mean thickness of 1.2
cm and a mean length of 8.3
cm. The thickened bowel enhanced homogeneously in nine patients and heterogeneously in the other nine. Inflammatory infiltration was mostly diffuse and severe. In 17 patients, a peritoneal or pelvic mass (mean maximum diameter, 3.2
cm) was seen adjacent to the involved bowel and appeared to be heterogeneously enhanced in most cases; infiltration into the abdominal wall was seen in four patients.
Actinomycosis should be included in the differential diagnosis when CT scans show bowel wall thickening and regional pelvic or peritoneal mass with extensive infiltration, especially in patients with abdominal pain, fever, leukocytosis, or long-term use of intrauterine contraceptive devices.
Neoplasms and other inflammatory diseases, especially tuberculosis or Crohn's disease, may be confused with actinomycosis. In actinomycosis, solid masses with focal low-attenuation areas were more frequently found than cystic masses with thickened walls. In conclusion, imaging investigations (US, CT, and MRI) confirm the presence of a mass with collections but they are not able to distinguish between actinomycosis and malignancy, Crohn's disease, diverticulitis, appendicitis, pelvic peritonitis, or tubercolosis [9
The infiltrative mass with unusual aggressiveness is the one of important radiological findings.
In our case the CT scan showed an infiltrative mass with unusual aggressiveness. The lymph node enlargement, ascites and involvement of the whole peritoneal cavity were absent. These findings could be supported by the diagnosis of Actinomycosis in our case.
Similarly to our case, in the great majority of cases, diagnosis is reached by histopathological examination of the specimen obtained by surgical exploration and resection. Histopathologic examination of the infected tissue should include a search for characteristic, but not pathognomonic, appearances of sulphur granules. The granules measure 0.4–4
mm and stain Gram-positive with a mycelium-like structure [10
]. The differential diagnosis of sulphur granules, however, includes nocardiosis, streptomycosis, chromomycosis, eumycetoma, and botryomycosis [11
granules regularly show a positive reaction with periodic acid Schiff and Grocott's dye, but the Kossa reaction is negative. Pseudoactinomyces granules formed by Nocardia
spp. show the opposite reactions [12
]. Because of the size of the bacterium, it usually does not spread via the lymphatic system; therefore, regional lymphadenopathy is uncommon or develops late [13
]. In our case the intense proliferation of fibroblasts and xanthomatous cells may be considered the cause of sizes of retroperitoneal mass simulating malignancy. The necrosis and abscess areas have progressively increased the inflammatory mass with compression and infiltration of adjacent organs. The histological examination showed regional lymph nodes free of disease.