title: Clinicopathological characteristics of lung cancer mimicking organizing pneumonia on computed tomography-a novel radiological entity of pulmonary malignancy.
abstract: OBJECTIVE
  Lung cancer could be misdiagnosed as benign due to its atypical radiological findings or difficulty in the histological diagnosis. We intended to elucidate the clinicopathological features of such lung cancers.
  
  
  METHODS
  Between 2008 and 2011, we performed surgical resection for 564 consecutive patients with lung adenocarcinoma. Findings on thin-section computed tomography were reviewed for all patients, 13 of whom were found to have lung cancer mimicking organizing pneumonia. The radiological and clinicopathological features of lung cancer mimicking organizing pneumonia and other adenocarcinomas were evaluated.
  
  
  RESULTS
  Among 13 patients with lung cancer mimicking organizing pneumonia, 4 were men. The median age was 70 years (range 62-81 years). Six patients were followed up for more than 1 year (range 1-108 months) as their lesions were misdiagnosed as organizing pneumonia. Preoperative carcinoembryonic antigen was significantly high (P = 0.025), and maximum tumor dimension was significantly large for lung cancer mimicking organizing pneumonia (30 vs. 23.6 mm, P = 0.001). Pathologically, there was no vascular invasion (P = 0.012) and only one lymphatic invasion (P = 0.064). One case of lymph node metastasis to the N2 node was found due to misdiagnosis as organizing pneumonia for 9 years.
  
  
  CONCLUSIONS
  Basically, lung cancer mimicking organizing pneumonia was less invasive and showed slow growth. However, nodal metastasis could be found. Thus, radiological diagnosis based on the findings of thin-section computed tomography is valuable to avoid delay in diagnosis.
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ichikawa
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Aritoshi
authors.initials: A
authors.lastname: Hattori
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takamochi
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shiaki
authors.initials: S
authors.lastname: Oh
authors.affiliation: Departments of General Thoracic Surgery, Diagnostic Radiology, and Surgical Pathology, Juntendo University School of Medicine, Tokyo, Japan kjsuzuki@juntendo.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: computed tomography; diagnosis; lung cancer