title: Clinicopathologic analysis of multiple (five or more) atypical adenomatous hyperplasias (AAHs) of the lung: evidence for the AAH-adenocarcinoma sequence.
abstract: OBJECTIVE
  Clarification of the clinicopathologic characteristics of patients with multiple atypical adenomatous hyperplasias (AAHs).
  
  
  METHODS
  The subjects were 1,639 patients who underwent lobectomy or pneumonectomy for lung tumors. The clinicopathologic features of the AAHs in the lung background and the main tumors were examined with regard to the number and the size of the AAHs, the incidence and histology of adenocarcinomas (ADs), and the outcome.
  
  
  RESULTS
  Thirty-two patients (2.0%) had 5 or more AAHs (ranging from 5 to 171), being present predominantly in the upper lobe (86%) and in women (75%). Among the 794 AAHs, 495 (62%) measured less than 1 mm, 170 (22%) measured 1 to less than 2 mm, 118 (15%) measured 2 to less than 5 mm, and 11 (1%) measured 5 to less than 10 mm. Twenty-eight patients (88%) had AD (1 in 18 patients and 2 to 6 in 10 patients). Thirty-two of the 51 patients with ADs (63%) had an AAH component. The incidence of ADs among the total of both AAHs and ADs was 6.0% (51 of 845). The 5-year cancer-free survival rate was 71.4%.
  
  
  CONCLUSIONS
  Five or more AAHs were seen in the background in 2.0% of lung tumors. Most of the AAHs were small, measuring less than 2 mm, and few exceeded 5 mm. Most of the patients had ADs, which were histologically suggested to be derived from AAH. However, the incidence of the AAH-AD sequence was considered to be low at the tumor basis, and the outcome of ADs was not very favorable.
authors.affiliation: Clinical Laboratory, National Cancer Center Hospital, Tokyo, Japan. akmaeshi@ncc.go.jp
authors.forename: Akiko Miyagi
authors.initials: AM
authors.lastname: Maeshima
authors.forename: Naobumi
authors.initials: N
authors.lastname: Tochigi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshida
authors.forename: Hisao
authors.initials: H
authors.lastname: Asamura
authors.forename: Koji
authors.initials: K
authors.lastname: Tsuta
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsuda
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000236:Adenoma / Q000473:pathology*; D000368:Aged; D018287:Carcinoma, Large Cell / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia; D008175:Lung Neoplasms / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate