title: Imaging of actinomycosis in various organs: a comprehensive review.
abstract: Actinomycosis is a chronic suppurative bacterial infection caused by Actinomyces species. Actinomyces israelii is the organism most commonly found in human disease. Actinomycosis usually manifests with abscess formation, dense fibrosis, and draining sinuses. The disease is further characterized by the tendency to extensively spread beyond normal fascial and connective tissue planes. Actinomycosis occurs most commonly in the cervicofacial region (50%-65%), followed by the thoracic (15%-30%) and abdominopelvic (20%) regions, but rarely involves the central nervous system. Most cases of cervicofacial actinomycosis are odontogenic in origin. In the acute form, cervicofacial disease can manifest with soft-tissue swelling, a painful pyogenic abscess, or a mass lesion. In the subacute to chronic form, a painless indurated mass can spread to the skin, leading to draining sinus tracts. Thoracic manifestations include parenchymal, bronchiectatic, and endobronchial actinomycosis. At computed tomography, pulmonary actinomycosis usually appears as chronic segmental airspace consolidation containing necrotic low-attenuation areas with peripheral enhancement. Abdominopelvic actinomycosis preferentially involves the ileocecal region, ovary, and fallopian tube. The imaging findings favoring abdominopelvic actinomycosis include strong enhancement in the solid portion of the mass after contrast material administration, small rim-enhancing abscesses within the mass, and extensive inflammatory extensions. Actinomycosis in the central nervous system may produce brain abscess, meningitis, subdural empyema, actinomycetoma, and spinal and cranial epidural abscess. In general, actinomycosis responds well to antibiotic therapy, but long-term follow-up after treatment is needed because of frequent relapses.
authors.affiliation: From the Department of Radiology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Jeollanam-do, Republic of Korea (S.H.H., J.W.K., H.S.L., H.J.S., Y.Y.J., H.K.K.); and the Departments of Radiology (S.S.S.) and Internal Medicine (S.I.J.) and the Center for Aging and Geriatrics (S.S.S.), Chonnam National University Hospital, Chonnam National University Medical School, 8 Hack-dong, Dong-gu, Gwang-ju 501-757, Republic of Korea.
authors.forename: Suk Hee
authors.initials: SH
authors.lastname: Heo
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Shin
authors.forename: Jin Woong
authors.initials: JW
authors.lastname: Kim
authors.forename: Hyo Soon
authors.initials: HS
authors.lastname: Lim
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Seon
authors.forename: Sook-In
authors.initials: SI
authors.lastname: Jung
authors.forename: Yong Yeon
authors.initials: YY
authors.lastname: Jeong
authors.forename: Heoung Keun
authors.initials: HK
authors.lastname: Kang
mesh_terms: D000196:Actinomycosis / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014781:Viscera / Q000000981:diagnostic imaging* / Q000473:pathology*