Presentation
Lower abdominal pain and swelling. History of laparoscopic treatment for ectopic tubal pregnancy four months earlier. Ultrasound exam revealed pelvic irregular (likely neoplastic mass), for further assessment.
Patient Data
A midline pelvic peritoneal irregular soft tissue lesion. The lesion looks aggressive and infiltrative invading the adjacent urinary bladder, the transverse colon, and the abdominal wall (at the site of recent surgical intervention). The mass appears heterogeneous. It elicits isointense to a high signal on T1 WI, and a high signal on T2 WI with internal cystic areas. It shows diffusion restriction with intense post-contrast enhancement and internal marginally enhancing cystic collections. Associated extensive edema and smudging of the peritoneum and the abdominal wall were noted.
Normal appearance of the uterus and both ovaries.
No pathologically enlarged deep pelvic lymph nodes.
Mild pelvic ascites.
Opinion: though the lesion appears aggressive and infiltrative, an aggressive inflammatory process is still considered because of the young age of the patient, recent surgical intervention, the involvement of the surgical scar site in the inflammatory process, the presence of internal marginally enhancing cystic (likely abscesses) collections within the lesion, the absence of deep pelvic lymphadenopathy, and the presence of an extensive edema and smudging of the peritoneal fat planes and abdominal wall.
Hence, an aggressive inflammatory process (likely actinomycosis) was highly considered in our report rather than the neoplastic possibility.
Non contrast CT scan of the pelvis the isodense irregular pelvic lesion showing internal indurated fat density and invading the abdominal wall, associated with extensive smudging of the omentum and peritoneum.
Her laboratory workup revealed:
Elevated C-reactive protein (107.0 mg/L) (Normal 0-10)
Alpha-fetoprotein (AFP) (0.9ng/mL) (Normal up to 8)
Carcinoembryonic antigen (CEA) 1.26 ng/mL) (Normal up to 3.0)
CA 19-9 5 (Normal 0-34)
Elevated CA 125 132.00 U/mL (Normal 0-35)
Serum LDH 224 U/L (Normal 135-214)
CBC: Mild hypochromic anemia with RBCs anistocytosis. Absolute lymphopenic.
The patient underwent surgical intervention with excision of the pelvic mass. The surgical report demonstrated a large pelvic abscess, which was treated by evacuation and excision.
Histopathology of the lesion showed:
Gross:
Multiple fibrofatty tissue pieces collectively measuring 10 × 7 × 4 cm. The cut section shows firm grey-white and yellow areas.
Microscopic:
Sections examined revealed a granulomatous reaction composed of granulomas with multinucleated giant cells, surrounded by inflammatory cells and histiocytes. The surrounding tissue is heavily infiltrated by neutrophils, along with debris and proliferating blood vessels. No malignancy.
Diagnosis:
pelvic abscess, evacuation and excision
non-caseating granulomatous inflammation with suppuration and abscess formation
no malignancy. For microbiology
Culture was positive for Actinomyces spp. (Actinomyces israelii).
Case Discussion
Pelvic actinomycosis (The great masquerader)
In this case, you can see the debate between the aggressive-looking infiltrative mass lesion invading the adjacent structures, which looks likely neoplastic (? urachal adenocarcinoma), and the other factors suggesting an inflammatory process including the young age of the patient, the start of the complaint shortly few months after a recent surgical intervention (treatment of ectopic tubal pregnancy), the radiological features of the lesion which would suggest an inflammatory process such as the internal indurated fat, the internal marginally enhancing cystic collections suggestive of abscesses, the extensive surrounding extensive omental/peritoneal smudging, the involvement of the abdominal wall and finally the absence of enlarged lymph nodes.
Also, the rest of the pelvic organs appear quite normal with a normal uterus and adnexa. The laboratory workup revealed elevated inflammatory markers (ESR and CRP), even the elevated CA 125 is not pathognomonic for cancers as it could be elevated in inflammatory processes like pelvic inflammatory diseases. in the end, the surgical intervention and histopathology confirmed an aggressive inflammatory process by Actinomyces spp (Actinomyces israelii).
Pelvic actinomycosis is a rare but serious infection caused by Actinomyces spp., an opportunistic gram-positive bacteria usually introduced by foreign bodies, particularly intra-uterine contraceptive devices, surgery (as in our case), or trauma. It generally falls under the broader spectrum of pelvic inflammatory disease.
Radiographic features usually show solid lesions which tend to be denser than tubo-ovarian abscesses originating from other organisms that can mimic a locally invasive malignancy.
Treatment is usually with intravenous penicillin in uncomplicated cases. Presence of an associated complication, such as a tubo-ovarian abscess, warrants surgical intervention.
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