Investig Magn Reson Imaging.  2019 Jun;23(2):136-141. 10.13104/imri.2019.23.2.136.

Pelvic Actinomycosis Mimicking Malignancy of the Uterus: a Case Report

• Shin D
• Hwang J
• Hong SS
• Lee EJ
• Kim YH

• KMID: 2452527
• DOI: http://doi.org/10.13104/imri.2019.23.2.136

Abstract

Pelvic actinomycosis is an uncommon infectious disease. It induces a chronic, suppurative illness characterized by an infiltrative and granulomatous response and, thus, the clinical and radiologic findings may mimic other inflammatory and neoplastic conditions. A 56-year-old female with a long-standing intrauterine device was diagnosed with pelvic actinomycosis manifesting as a large uterine mass with locally infiltrative spread into surrounding tissue that mimicked uterine malignancy. Actinomyces israelii infection was confirmed with a surgical specimen, and the patient was treated with antibiotic medication. Pelvic actinomycosis must be included in the differential diagnoses of patients with an infiltrative pelvic mass extending across tissue planes or in patients with findings of multiple microabscesses, particularly in a patient with an intrauterine device, even the lesion primarily involves the uterus.

Keyword

Actinomycosis; Neoplasms; Pelvic inflammatory disease; Uterus

MeSH Terms

Actinomyces
Actinomycosis*
Communicable Diseases
Diagnosis, Differential
Female
Humans
Intrauterine Devices
Middle Aged
Pelvic Inflammatory Disease
Uterus*

Figure

• 

  Fig. 1 A contrast-enhanced abdominal axial (a) and coronal (b) reformatted CT images on initial presentation showed diffuse enlargement of the uterus with a poorly defined, heterogeneously enhancing lesion. There was an IUD in situ (arrow).

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  Fig. 2 A follow-up contrast-enhanced abdominal axial (a) and coronal (b) reformatted CT images 3 months after initial presentation showed enlarged heterogeneously enhancing uterine lesion with multiple focal areas of low-attenuation. There was an IUD in situ (arrow). The adjacent sigmoid colon showed mild luminal narrowing with wall thickening, and there was soft tissue stranding in the surrounding mesocolon (arrowhead).

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  Fig. 3 (a) MRI revealed mild high signal intensity uterine mass with a poorly defined margin, small cystic foci on the axial T2-weighted image (arrows), and (b) heterogeneous enhancement with multiple, tiny, hypointense foci with ring-like enhancement on gadolinium-enhanced fat-suppressed T1-weighted image (arrows). The lesion showed diffusion restriction on diffusion weighted imaging (c, d).

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  Fig. 4 On 18F FDG PET/CT, the lesion was highly avid (SUVmax = 20.0 g/ml). Diffuse hypermetabolism was also seen in the bone marrow cavity of the whole skeletal system. FDG PET/CT = fluoro-deoxyglucose positron emission tomography/computed tomography, SUVmax = maximum standardized uptake value.

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  Fig. 5 On cut sections of the uterine gross specimen (a), a huge globoid uterine corpus revealed a markedly thickened myometrium showing multifocal, ill-defined abscesses and pus-like material. (b) Histopathologic features showed a sulfur granule in an inflammatory exudate (Hematoxylin & Eosin stain, × 100).

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