title: Salivary duct carcinoma and the concept of early carcinoma ex pleomorphic adenoma.
abstract: OBJECTIVE
  The data on the histological type of carcinomatous component and the extent of extracapsular invasion for salivary carcinomas ex pleomorphic adenoma (PA) are conflicting. We aimed to determine the prognostic value of extracapsular invasion in salivary duct carcinomas (SDC) ex PA.
  
  
  RESULTS
  A total of 117 patients with SDC were identified retrospectively; 44 cases involving major salivary glands had pre-existing PA (44 of 117, 37%). The morphological spectrum of SDC ex PA was characterized. The primary endpoint was overall survival (OS). Most SDC ex PA were widely invasive at presentation (27 of 44; 61%). Five patients with intracapsular SDC ex PA experienced no disease progression. The assessment of extracapsular invasion was precluded in eight cases (e.g. positive margins of resection). The rate of lymph node involvement was similar in cases with extracapsular invasion of ≤2 mm (two of three) and >7 mm (22 of 26). Only pT correlated with OS [116 months, 95% confidence interval (CI) 22-210 months for pT1 versus 20 months (95% CI 6-34) for pT4; P = 0.013].
  
  
  CONCLUSIONS
  Intracapsular SDC ex PA are potentially indolent. SDC ex PA with extracapsular invasion of ≤2 mm are rare, and appear to be clinically aggressive. Several histological parameters preclude assessment of extracapsular invasion.
authors.affiliation: Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Griffith
authors.forename: Lester D R
authors.initials: LD
authors.lastname: Thompson
authors.forename: Adel
authors.initials: A
authors.lastname: Assaad
authors.forename: Bibianna M
authors.initials: BM
authors.lastname: Purgina
authors.forename: Chi
authors.initials: C
authors.lastname: Lai
authors.forename: Julie E
authors.initials: JE
authors.lastname: Bauman
authors.forename: Ilan
authors.initials: I
authors.lastname: Weinreb
authors.forename: Raja R
authors.initials: RR
authors.lastname: Seethala
authors.forename: Simion I
authors.initials: SI
authors.lastname: Chiosea
mesh_terms: D008949:Adenoma, Pleomorphic / Q000401:mortality / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000401:mortality / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018987:Salivary Ducts / Q000473:pathology; D012468:Salivary Gland Neoplasms / Q000401:mortality / Q000473:pathology*
keywords: early carcinoma ex pleomorphic adenoma; minimal invasion; pT in-situ stage; salivary duct carcinoma