title: Sarcoid-like reaction-computed tomography features in 12 patients.
abstract: OBJECTIVE
  The aim of the study was to analyze the computed tomography (CT) findings of sarcoid-like reaction caused by underlying malignancy or immune modulation.
  
  
  METHODS
  Twelve patients with pathologically proven sarcoidosis from underlying causes (malignancies, hepatitis C infection, and immune-modulatory treatment) in 2001 to 2011 were identified. All patients had chest CT scans, which were reviewed by 3 experienced thoracic radiologists. Medical records were also reviewed. Follow-up imaging, available in 11 patients, was assessed for response.
  
  
  RESULTS
  All patients were white, 8 women and 4 men, with ages ranging from 26 to 72 years. Seven had underlying malignancy, 2 had inflammatory bowel disease, and 3 had liver disease caused by chronic hepatitis C viral infection. On CT, 92% (11/12) of patients had lymphadenopathy, 75% (9/12) had pulmonary nodules less than 5 mm, and 50% (6/12) had ground-glass opacity (GGO). In 42% (5/12) of patients, the dominant finding was discrete nodules (1-5 mm). In 33% (4/12) of patients, the dominant finding was ultrafine nodules with confluence, mimicking GGO. The most common distribution of lung nodules was perilymphatic, found in 78% (7 of the 9 patients with lung nodules). Follow-up was available in 10 patients, limited follow-up in 1, and no follow-up in 1. Six of the 11 patients who had follow-up had complete resolution of CT findings, 3 had partial resolution, and 2 had no resolution.
  
  
  CONCLUSIONS
  Imaging features of patients with sarcoid-like reaction include lymphadenopathy, small nodules, and ultrafine nodules with confluence, mimicking GGO. Ultrafine nodules with confluence mimicking GGO were unexpectedly common in this series.
authors.affiliation: From the *Department of Radiology, University of Washington and †Department of Radiology, Puget-Sound VA Health Care System, Seattle, WA.
authors.forename: Randy K
authors.initials: RK
authors.lastname: Lau
authors.forename: Julie E
authors.initials: JE
authors.lastname: Takasugi
authors.forename: J
authors.initials: J
authors.lastname: David Godwin
authors.forename: Sudhakar N J
authors.initials: SN
authors.lastname: Pipavath
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012507:Sarcoidosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed