title: [Collision tumor of a hypopharyngeal adenoidcystic carcinoma and a laryngeal squamous cell carcinoma].
abstract: BACKGROUND
  Malignancies in head and neck cancer are mainly squamous cell carcinomas. Adenoid cystic carcinomas are rare lesions of this site. Laryngeal adenoid cystic carcinoma is estimated to occur in 0.1 - 0.7 % of all laryngeal carcinomas. Adenoid cystic carcinomas are rarely located in the hypopharynx. To our knowledge there is no case report of adenoid cystic carcinoma of the hypopharynx as part of a collision tumor of the larynx.
  
  
  METHODS
  A 47-year-old male patient was diagnosed with an adenoid cystic carcinoma of the hypopharynx and a squamous cell carcinoma of the larynx. Because of local extension of both tumors laryngectomy and partial pharyngotomy with bilateral neck dissection was performed followed by radiation therapy. Clinical aspects as well as histomorphological and immunohistochemical criteria of both tumor entities are discussed.
  
  
  CONCLUSIONS
  Immunohistochemical characteristics showed two different carcinoma entities in the larynx and hypopharynx. Only by complete histological investigation of a carcinoma those rare cases of a collision tumor can be detected. Both tumor entities need to be considered for therapy strategy and oncological follow-up planning.
authors.affiliation: Klinik für Hals-, Nasen- und Ohrenkrankheiten, Kopf- und Halschirurgie der Ruhr-Universität Bochum, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kufeld
authors.forename: K
authors.initials: K
authors.lastname: Junker
authors.forename: H
authors.initials: H
authors.lastname: Sudhoff
authors.forename: S
authors.initials: S
authors.lastname: Dazert
mesh_terms: D003528:Carcinoma, Adenoid Cystic / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D007013:Hypopharynx / Q000473:pathology; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D007825:Laryngectomy; D007830:Larynx / Q000473:pathology; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009378:Neoplasms, Multiple Primary / Q000473:pathology; D010611:Pharyngectomy; D013997:Time Factors; D016896:Treatment Outcome