title: Clinically aggressive metastasizing pleomorphic adenoma: report of two cases.
abstract: BACKGROUND
  It has been suggested that metastasizing pleomorphic adenomas may represent unrecognized malignancy.
  
  
  METHODS
  The cytologic and clinical characteristics of two metastasizing pleomorphic adenomas diagnosed by fine-needle sampling are reported.
  
  
  RESULTS
  Both showed malignant evolution: the primary tumors arose from the palate and the parotid salivary glands, respectively. Metastases occurred simultaneously with local recurrence in the first patient and after a second local recurrence in the second patient. Both patients were treated by surgery and radiotherapy but died of disseminated disease 8 and 4 years after initial diagnosis. No histologic evidence of malignancy was observed on cytology smears or histology sections in either case.
  
  
  CONCLUSIONS
  Clinically, our cases support the hypothesis that metastasizing pleomorphic adenomas represent unrecognized malignancy, because the biologic course of two tumors led to unequivocally lethal outcome.
authors.affiliation: Department of Pathology, Institut Curie, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Klijanienko
authors.forename: A K
authors.initials: AK
authors.lastname: El-Naggar
authors.forename: V
authors.initials: V
authors.lastname: Servois
authors.forename: J
authors.initials: J
authors.lastname: Rodriguez
authors.forename: P
authors.initials: P
authors.lastname: Validire
authors.forename: P
authors.initials: P
authors.lastname: Vielh
mesh_terms: D008949:Adenoma, Pleomorphic / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D001707:Biopsy, Needle; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010157:Palatal Neoplasms / Q000473:pathology; D012468:Salivary Gland Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery