title: Primary neuroendocrine carcinoma of the appendix: a case report and review of the literature.
abstract: OBJECTIVE
  We report on a rare case of appendiceal primary neuroendocrine carcinoma (NEC) and discuss three cases previously described.
  
  
  METHODS
  A 58-year-old woman presented with acute abdominal pain and a low-grade fever. She was diagnosed with acute appendicitis and underwent laparoscopic appendectomy. Pathological examination of the resected specimen revealed NEC. Immunohistochemical analyses were positive for synaptophysin, chromogranin, and CD-56. The tumour was high grade and the Ki-67 index was >20%. Primary NEC of the appendix is extremely rare. To our knowledge, this is the first case report of an appendiceal NEC that meets the 2010 diagnostic criteria of the World Health Organization.
  
  
  CONCLUSIONS
  Due to its non-specific clinical presentation, NEC is often misdiagnosed as appendicitis; however, it can advance rapidly and carries a very poor prognosis, despite chemotherapy. In the future, a treatment protocol for immunohistochemical analyses should be established to improve the survival rate.
authors.affiliation: Department of Gastroenterological Surgery, Shiroyama Hospital, Ota, Gunma, Japan.
authors.forename: Kodai
authors.initials: K
authors.lastname: Tomioka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fukoe
authors.forename: Yugen
authors.initials: Y
authors.lastname: Lee
authors.forename: Masahiro
authors.initials: M
authors.lastname: Lee
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Wada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aoki
authors.forename: Masahiko
authors.initials: M
authors.lastname: Murakami
mesh_terms: D001062:Appendectomy; D001063:Appendiceal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D001064:Appendicitis / Q000175:diagnosis*; D001065:Appendix / Q000473:pathology / Q000601:surgery; D019002:CD56 Antigen / Q000378:metabolism; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D002864:Chromogranins / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D010535:Laparoscopy; D008875:Middle Aged; D011859:Radiography; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D019002:CD56 Antigen; D002864:Chromogranins; D019394:Ki-67 Antigen; C569014:SYP protein, human; D016708:Synaptophysin
keywords: NEC; NET; Neuroendocrine; appendix; carcinoma