title: Large liposarcoma developing in the ischiorectal fossa: Report of a rare case.
abstract: BACKGROUND
  We herein report an extremely rare case of a liposarcoma developing in the ischiorectal fossa that was completely resected using a transsacral approach.
  
  
  METHODS
  A 74-year-old man was admitted to our institute because of a large perianal tumor. A pelvic magnetic resonance imaging (MRI) revealed an 8cm×7cm×5cm sized encapsulated heterogeneous tumor on the right side of the ischiorectal fossa. Transsacral excision was performed under a diagnosis of liposarcoma. The tumor was partially fixed to the external sphincter and puborectalis. Therefore, the muscles were partially resected to ensure sufficient margins. Histopathological examination revealed a well differentiated liposarcoma and negative surgical margins.
  
  
  CONCLUSIONS
  The basic treatment strategy of liposarcoma is surgical resection, whereas the effects of chemotherapy or radiotherapy remain limited. Although no postoperative adjuvant therapy has been performed in our case, no recurrences have occurred for 1 year after surgery.
  
  
  CONCLUSIONS
  Although the curative resection of large tumors located in the ischiorectal fossa is usually difficult, the complete resection of liposarcoma is the main potentially curative treatment. A transsacral approach is useful for a complete resection.
authors.affiliation: Department of Surgery, Keio University School of Medicine, Japan. Electronic address: seishima@a3.keio.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Seishima
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Endo
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ochiai
authors.forename: Koji
authors.initials: K
authors.lastname: Okabayashi
authors.forename: Makio
authors.initials: M
authors.lastname: Mukai
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kitagawa