title: Pleomorphic adenoma of the parotid gland 1985-2010: A Danish nationwide study of incidence, recurrence rate, and malignant transformation.
abstract: Pleomorphic adenoma is the most frequent salivary gland tumor and is known for its tendency to recur and for its ability to transform to carcinoma ex pleomorphic adenoma (Ca-ex-PA). Along with pleomorphic adenoma demographics, we present the first nationwide study with long-term follow-up on these topics.
  
  
  
  The Danish Pathology Data Bank was searched for parotid pleomorphic adenoma and Ca-ex-PA in the period 1985 to 2010 and all pathology descriptions were reviewed. Ca-ex-PA specimens were reviewed by a pathologist.
  
  
  
  A total of 5.497 patients were identified and 2.86% had at least one recurrence. An incidence of 4.29/100,000/year was found. The rate of malignant transformation in recurrent pleomorphic adenoma was 3.3%.
  
  
  
  We report an up-to-date assessment of the epidemiology of pleomorphic adenoma. We found an increasing incidence and low recurrence rate compared with previous studies. The risk of Ca-ex-PA for patients with recurrent pleomorphic adenoma was low compared to the literature. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1364-E1369, 2016.
authors.affiliation: Department of Otorhinolaryngology and Maxillofacial Surgery, Køge University Hospital, Køge, Denmark.|Department of Otolaryngology Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark.|University of Copenhagen, Copenhagen, Denmark.
authors.forename: Simon
authors.initials: S
authors.lastname: Andreasen
authors.affiliation: Department of Pathology, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Marianne H
authors.initials: MH
authors.lastname: Therkildsen
authors.affiliation: Department of ORL-Head and Neck Surgery, Odense University Hospital, Odense, Denmark.
authors.forename: Kristine
authors.initials: K
authors.lastname: Bjørndal
authors.affiliation: Department of Otorhinolaryngology and Maxillofacial Surgery, Køge University Hospital, Køge, Denmark.|University of Copenhagen, Copenhagen, Denmark.
authors.forename: Preben
authors.initials: P
authors.lastname: Homøe
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000473:pathology; D008949:Adenoma, Pleomorphic / Q000453:epidemiology* / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D010306:Parotid Gland / Q000473:pathology; D010307:Parotid Neoplasms / Q000453:epidemiology* / Q000473:pathology; D055815:Young Adult
keywords: carcinoma; epidemiology; parotid; pleomorphic adenoma