title: Primary leiomyosarcoma of the colon.
abstract: Primary leiomyosarcomas of the gastrointestinal (GI) tract are extremely rare and highly aggressive neoplasms, and only a small number of true cases have been reported since the concept of GI stromal tumors was established. Here, we report a case of a primary leiomyosarcoma of the transverse colon. A 46-year-old Japanese male with a large mass in the right upper abdomen was admitted to our hospital. Computed tomography and magnetic resonance imaging revealed long segments of wall thickening of the transverse colon with large consecutive tumors measuring 12 cm in diameter. A projecting irregular mass with marked mucosal necrosis was found on colonoscopy. Pathological examination revealed a spindle cell tumor growing circumferentially and transmurally to replace the muscularis propria in the transverse colon. The spindle cells were positive for smooth muscle actin, and negative for KIT, CD34, DOG-1, and S-100 protein. The patient has shown repeat recurrence in spite of sufficient surgical excision being promptly performed.
authors.affiliation: Department of Gastroenterology, Sakai Hospital Kinki University Faculty of Medicine, 2-7-1 Harayamadai, Minamiku, Sakai, 590-0132, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kono
authors.forename: Naoko
authors.initials: N
authors.lastname: Tsuji
authors.forename: Nobuto
authors.initials: N
authors.lastname: Ozaki
authors.forename: Nozomu
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Takehisa
authors.initials: T
authors.lastname: Takaba
authors.forename: Naoki
authors.initials: N
authors.lastname: Okumura
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Takafumi
authors.initials: T
authors.lastname: Tomita
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Umehara
authors.forename: Satoko
authors.initials: S
authors.lastname: Taniike
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hatabe
authors.forename: Sadao
authors.initials: S
authors.lastname: Funai
authors.forename: Yukihhiko
authors.initials: Y
authors.lastname: Ono
authors.forename: Ken
authors.initials: K
authors.lastname: Ochiai
authors.forename: Shunji
authors.initials: S
authors.lastname: Maekura
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kudo
mesh_terms: D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D006801:Humans; D007890:Leiomyosarcoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local