title: Solitary synovial chondromatosis arising in the gluteus maximus bursa: computed tomography and magnetic resonance imaging findings.
abstract: Chondral tumors in soft tissue are referred to as soft-tissue chondromas or extraskeletal chondromas, or as synovial chondromatosis if they arise in synovial tissue. We report the case of a 29-year-old man with synovial chondromatosis, also called synovial osteochondromatosis, which appeared in a solitary and extra-articular form. On magnetic resonance imaging (MRI) and computed tomography, the central portion of the tumor showed similar characteristics to bone marrow, despite the absence of any connection to adjacent bone. T2-weighted imaging displayed marked peripheral hyperintensity consistent with a cartilaginous area. These findings suggested the presence of enchondral ossification and were similar to those of skeletal osteochondroma, with the exception of the absence of attachment to bone. MRI is useful for distinguishing solitary synovial chondromatosis from other lesions, such as myositis ossificans, extraskeletal chondrosarcoma, and parosteal osteosarcoma.
authors.affiliation: Department of Radiology, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan; Department of Radiology, National Center Hospital of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sumida
authors.affiliation: Department of Radiology, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Department of Radiology, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nambu
authors.affiliation: Department of Radiology, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Tago
authors.affiliation: Department of Orthopedics, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Shibuya
authors.affiliation: Department of Diagnostic Pathology, Teikyo University Mizonokuchi Hospital, Kanagawa, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kawamoto
keywords: Synovial chondromatosis; extraskeletal osteochondroma; gluteus maximus bursa; magnetic resonance imaging (MRI)