title: Fine needle aspiration cytology of dedifferentiated acinic cell carcinoma of the parotid gland: a case report.
abstract: BACKGROUND
  Dedifferentiation of acinic cell carcinoma (ACC) to undifferentiated carcinoma occurs rarely and entails a poor prognosis. Most cases of dedifferentiation occur as recurrences of a previously excised ACC. More rarely the neoplasm presents with areas of well-differentiated ACC coexisting with dedifferentiated ones.
  
  
  METHODS
  An 85-year-old man presented with 2 nodular areas in the right parotid area. Fine needle aspiration of both nodules was performed. In both cases cytology revealed a double epithelial component in similar proportions. The first one corresponded to cohesive groups of small to intermediate-sized, polygonal cells with round, monomorphic nuclei. They were distributed in small and larger, branching groups with acinic morphology. Intermixed with this population, irregular groups of larger, pleomorphic cells with irregular nuclei, prominent nucleoli and scarce cytoplasm were present. In addition, smears showed an abundant lymphoid background. A cytologic diagnosis of "salivary carcinoma with coexisting areas of acinic cell differentiation and high grade, undifferentiated carcinoma" was given. Histopathology revealed a well-differentiated ACC with areas of high grade undifferentiated carcinoma (dedifferentiated ACC).
  
  
  CONCLUSIONS
  The current case expands the cytomorphologic spectrum of ACC. Cytology may permit the preoperative recognition of dedifferentiation, allowing a more sound therapeutic approach.
authors.affiliation: Department of Pathology, University Hospital, Guadalajara, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: González-Peramato
authors.forename: José A
authors.initials: JA
authors.lastname: Jiménez-Heffernan
authors.forename: Pilar
authors.initials: P
authors.lastname: López-Ferrer
authors.forename: Blanca
authors.initials: B
authors.lastname: Vicandi
authors.forename: José M
authors.initials: JM
authors.lastname: Viguer
mesh_terms: D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000175:diagnosis* / Q000473:pathology; D018267:Carcinoma, Acinar Cell / Q000175:diagnosis* / Q000473:pathology; D002454:Cell Differentiation; D004847:Epithelial Cells / Q000473:pathology*; D006801:Humans; D008297:Male; D010306:Parotid Gland / Q000473:pathology*; D010307:Parotid Neoplasms / Q000175:diagnosis* / Q000473:pathology