title: [Successful resection of a gastrointestinal stromal tumor in the pelvis with imatinib mesylate as neoadjuvant therapy].
abstract: We report a case of marginally resectable gastrointestinal stromal tumor (GIST) in the pelvis treated with neoadjuvant intent before subsequent successful surgical resection. A 46-year old man presented with urinary frequency and rectal discomfort with tenesmus. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 12 cm diameter mass between the bladder and rectum and the margin of the tumor and prostate was unclear. No metastases were evident. Trans-rectal needle core biopsy confirmed c-kit positive GIST. Because of the locally advanced nature of the tumor,immediate surgical resection would have required total pelvic exenteration with eternal colostomy and urinary diversion. Therefore,the patient was treated with imatinib mesylate 400 mg daily in anticipation of adequate tumor size reduction to enable a more simplified surgical approach. After 3 months of imatinib therapy,MRI demonstrated a reduction in tumor size of 60%. Consequently,a complete surgical resection including the bladder,prostate and part of the sigmoid colon with temporary ileostomy and ileal conduit was performed. Pathological findings of the resected specimen showed widespread degeneration with cystic changes,necrosis, and hypocellularlity,as well as nodules of residual viable c-kit positive tumor cells. The patient has been treated with imatinib mesylate for 39 months following the operation without tumor recurrence.
authors.affiliation: The Department of Urology, Tokai University.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Nakajima
authors.forename: Seiichi
authors.initials: S
authors.lastname: Kato
authors.forename: Yukio
authors.initials: Y
authors.lastname: Usui
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shinozaki
authors.forename: Shuichi
authors.initials: S
authors.lastname: Soeda
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kawakami
authors.forename: Hakushi
authors.initials: H
authors.lastname: Kim
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hanai
authors.forename: Akio
authors.initials: A
authors.lastname: Hoshi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nomoto
authors.forename: Toshiro
authors.initials: T
authors.lastname: Terachi
authors.forename: Sotaro
authors.initials: S
authors.lastname: Sadahiro
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D046152:Gastrointestinal Stromal Tumors / Q000601:surgery / Q000628:therapy*; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D010386:Pelvic Neoplasms / Q000601:surgery / Q000628:therapy*; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate