title: Sacrococcygeal yolk sac tumor developing after teratoma: a clinicopathological study of pediatric sacrococcygeal germ cell tumors and a proposal of the pathogenesis of sacrococcygeal yolk sac tumors.
abstract: OBJECTIVE
  We evaluated the clinicopathological characteristics of pediatric sacrococcygeal germ cell tumors (SGCTs) and yolk sac tumors (YSTs) developing after sacrococcygeal teratoma (SCT) resection, and discussed the pathogenesis of sacrococcygeal YST.
  
  
  METHODS
  We retrospectively analyzed pediatric SGCT patients attending 10 Japanese institutions.
  
  
  RESULTS
  A total of 289 patients were eligible, of which 74.6% were girls. The mean age at surgery was 7.1months. There were 194 mature and 47 immature teratomas, and 48 YSTs. YST developed after SCT resection in 13 patients (5.4% of SCTs), and was detected between 5 and 30months after resection. At initial surgery, 9 of these 13 patients were neonates, 12 underwent gross complete resection with coccygectomy, and 9 had histologically mature teratoma without microscopic YST foci. Postoperative serum alpha-fetoprotein (AFP) levels were regularly examined in 11 patients. Intervals of AFP measurement≤4months helped to detect subclinical localized YSTs for resection.
  
  
  CONCLUSIONS
  The characteristics of SGCT in Japanese children were similar with those reported in Europe or the United States. YST developed after SCT resection not only in patients with previously reported risk factors. We recommend that patients undergo serum AFP monitoring every 3months for≥3years after SCT resection.
authors.affiliation: Division of Diagnostic Pathology, Kanagawa Children's Medical Center, Yokohama, 232-8555, Japan. mariko_yo_shi_da@ybb.ne.jp
authors.forename: Mariko
authors.initials: M
authors.lastname: Yoshida
authors.forename: Kentaro
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakazawa
authors.forename: Makiko
authors.initials: M
authors.lastname: Yoshida
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inoue
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kishimoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakayama
authors.forename: Emi
authors.initials: E
authors.lastname: Takaba
authors.forename: Minoru
authors.initials: M
authors.lastname: Hamazaki
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Horie
authors.forename: Mio
authors.initials: M
authors.lastname: Tanaka
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Gomi
authors.forename: Youkatsu
authors.initials: Y
authors.lastname: Ohama
authors.forename: Hisato
authors.initials: H
authors.lastname: Kigasawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kitano
authors.forename: Hiroo
authors.initials: H
authors.lastname: Uchida
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kanamori
authors.forename: Tadashi
authors.initials: T
authors.lastname: Iwanaka
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D003131:Combined Modality Therapy; D018240:Endodermal Sinus Tumor / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008297:Male; D012189:Retrospective Studies; D012445:Sacrococcygeal Region / Q000473:pathology* / Q000601:surgery*; D013724:Teratoma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D000509:alpha-Fetoproteins