title: Multicentric myofibroblastic sarcoma.
abstract: We report a case of synchronous, multicentric low-grade myofibroblastic sarcoma presenting in a 62-year-old man. He initially presented with inflammatory symmetric polyarthritis and adhesive capsulitis of his shoulder and hips bilaterally and did not respond to a trial of disease modifying antirheumatic drugs. Over a period of several years he developed progressive restriction of both knees and nodules on his hands, both knees and back. A biopsy of the nodule on his back was inconclusive and subsequent biopsies on his left and then right knee revealed a spindle cell neoplasm with an infiltrative growth pattern, mitotic figures, positive immunostaining for smooth muscle actin and focal myxoid change consistent with myofibroblastic sarcoma. While myofibroblastic sarcoma has been known to metastasise, to our knowledge, a multifocal presentation of this tumour has not been described previously.
authors.affiliation: Rheumatology Unit, Royal Adelaide Hospital and Flinders University School of Medicine, Adelaide, South Australia, Australia.
authors.forename: Mihir Dilip
authors.initials: MD
authors.lastname: Wechalekar
authors.affiliation: Department of Radiology, Flinders Medical Centre, Adelaide, South Australia, Australia.
authors.forename: Oliver
authors.initials: O
authors.lastname: Ayres
authors.affiliation: SA Pathology, and Discipline of Medicine, Adelaide University, Adelaide, South Australia, Australia.
authors.forename: Gelareh
authors.initials: G
authors.lastname: Farshid
authors.affiliation: Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Clayer
authors.affiliation: Rheumatology Unit, Royal Adelaide Hospital and Flinders University School of Medicine, Adelaide, South Australia, Australia.
authors.forename: Leslie G
authors.initials: LG
authors.lastname: Cleland
mesh_terms: D005354:Fibrosarcoma / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000473:pathology*; D009217:Myosarcoma / Q000473:pathology*; D009364:Neoplasm Recurrence, Local; D009379:Neoplasms, Muscle Tissue / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000473:pathology*