title: Intramuscular spindle cell lipoma of the deltoid: a case report.
abstract: BACKGROUND
  Spindle cell lipoma is an uncommon adipocytic tumor. Intramuscular lesions of this tumor are very rare. In this report, we describe a case of a patient with intramuscular spindle cell lipoma localized in a deltoid.
  
  
  METHODS
  A 58-year-old Japanese man visited us because of a soft tissue mass on the lateral aspect of the left shoulder that had been noticed 2 years prior. The spherical tumor, which measured 5 cm × 4 cm, was elastic and firm on palpation and immobile. Magnetic resonance imaging revealed that the lesion was localized in the left deltoid muscle. A needle biopsy was performed to make a histological diagnosis. With a pre-operative diagnosis of intramuscular lipoma, we removed the tumor with the patient under general anesthesia. The tumor was removed with surrounding musculature and fascia. The pathological diagnosis was intramuscular spindle cell lipoma in the left deltoid muscle.
  
  
  CONCLUSIONS
  There are several kinds of lipomas. Spindle cell lipoma is a relatively rare variant (1.5% of all adipocytic neoplasms) that is histologically distinct and characterized by the replacement of mature fat by a mixture of mature adipocytes and undifferentiated spindle cells. There are only five other reported cases of intramuscular spindle cell lipoma in the literature, to our knowledge. The case of our patient is very interesting, as to date there have been few reported patients with a diagnosis of an intramuscular spindle cell lipoma in a deltoid.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. mizo715@koto.kpu-m.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Mizoshiri
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. shi-ra-e@med.kanazawa-u.ac.jp.|Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan. shi-ra-e@med.kanazawa-u.ac.jp.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Shirai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. ryutel@mbox.kyoto-inet.or.jp.
authors.forename: Ryu
authors.initials: R
authors.lastname: Terauchi
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. yarai89046@nike.eonet.ne.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. fjwr@koto.kpu-m.ac.jp.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Pathology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. ekonishi@koto.kpu-m.ac.jp.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Konishi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan. tsuchi@med.kanazawa-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan. tkubo@koto.kpu-m.ac.jp.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D057645:Deltoid Muscle / Q000473:pathology*; D006801:Humans; D008067:Lipoma / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000175:diagnosis*; D012782:Shoulder / Q000473:pathology