title: Frozen section diagnoses of small pulmonary nodules: accuracy and clinical implications.
abstract: BACKGROUND
  Pulmonary nodules are frequently first diagnosed by frozen section, immediately followed by lobectomy or other procedures. The frozen section diagnosis of pulmonary nodules can be difficult, as inflammatory and fibrotic lesions can be confused for malignancy, creating intraoperative dilemmas for pathologists and thoracic surgeons.
  
  
  METHODS
  We reviewed our experience at Cedars-Sinai Medical Center with the frozen section diagnoses of 183 consecutive pulmonary nodules smaller than 1.5 cm in diameter and calculated the sensitivity, specificity, and predictive values of this diagnostic procedure.
  
  
  RESULTS
  One hundred and seventy four nodules were correctly classified by frozen section as neoplastic or nonneoplastic, six lesions were diagnosed equivocally, and two neoplasms were missed owing to sampling errors. The equivocal frozen section diagnoses included two bronchioloalveolar carcinomas (BAC) interpreted as "atypical hyperplasia, favor BAC," two BAC diagnosed as "alveolar hyperplasia," and two carcinoid tumors labeled as "atypical carcinoma" and "spindle cell lesion, carcinoid versus sclerosing hemangioma," respectively. The sensitivities for a diagnosis of neoplasia were 86.9% and 94.1% for nodules smaller than 1.1 cm in diameter and measuring 1.1 to 1.5 cm, respectively. The diagnostic accuracy of frozen sections was significantly better in nodules larger than 1.0 cm in diameter (p = 0.05). There were no false-positive diagnoses of malignancy, resulting in 100% specificity.
  
  
  CONCLUSIONS
  Intraoperative consultation with frozen section is a sensitive and specific procedure for the diagnosis of malignancy from small pulmonary nodules. The distinction between BAC and atypical adenomatous hyperplasia, and of small peripheral carcinoid tumors from other lesions, can be difficult by frozen section. Thoracic surgeons need to become aware of these problems and develop appropriate therapeutic strategies.
authors.affiliation: Department of Pathology and Laboratory Medicine, Cedars Sinai Medical Center, Los Angeles, California 90048, USA. marchevsky@cshs.org
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Marchevsky
authors.forename: Chanikarn
authors.initials: C
authors.lastname: Changsri
authors.forename: Indu
authors.initials: I
authors.lastname: Gupta
authors.forename: Clark
authors.initials: C
authors.lastname: Fuller
authors.forename: Ward
authors.initials: W
authors.lastname: Houck
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McKenna
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000175:diagnosis / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000473:pathology; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000473:pathology*; D018288:Carcinoma, Small Cell / Q000175:diagnosis / Q000473:pathology; D015331:Cohort Studies; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005188:False Negative Reactions; D005260:Female; D005629:Frozen Sections; D006801:Humans; D006965:Hyperplasia; D008171:Lung Diseases / Q000175:diagnosis* / Q000473:pathology; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D047868:Pulmonary Sclerosing Hemangioma / Q000175:diagnosis / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery