[Atypical computed tomography manifestations of thoracic sarcoidosis]

Objective: This study evaluated the atypical computed tomography (CT) manifestations of thoracic sarcoidosis. Methods: Medical data of 190 patients with thoracic sarcoidosis were retrospectively reviewed. Results: The atypical CT manifestations of thoracic sarcoidosis observed were unilateral hilar lymphadenopathy with or without mediastinal lymphadenopathy(n=12, 6.3%), mediastinal lymphadenopathy without hilar lymphadenopathy(n=9, 4.7%), patchy consolidation (n=23, 12.1%), sarcoid galaxy sign (n=22, 11.6%), reversed halo sign (n=1, 0.5%), and ground-glass opacities (n=52, 27.4%). Air trapping was found in 8 of 10 patients who underwent both inspiratory and expiratory CT. Post-treatment CT scans showed improvements in most patients. Of the 12 patients with unilateral hilar lymphadenopathy with or without mediastinal lymphadenopathy, 10(83.3%) improved. Of the 9 patients with mediastinal lymphadenopathy without hilar lymphadenopathy, 8(88.9%) improved. Of the 23 patients with patchy consolidation, 15(65.2%) improved. Of the 22 patients with the sarcoid galaxy sign, 16(72.7%) improved. The patient with the reversed halo sign improved completely. Of the 52 patients with ground-glass opacities, 31(59.6%) improved. Of the 8 patients with air trapping, 7(87.5%) improved. Conclusions: The atypical imaging manifestations of thoracic sarcoidosis included unilateral hilar lymphadenopathy with or without mediastinal lymphadenopathy, mediastinal lymphadenopathy without hilar lymphadenopathy, patchy consolidation, the sarcoid galaxy sign, the reversed halo sign, ground-glass opacity, and air trapping. These lesions mostly improved after treatment. Familiarity with these atypical signs will help increase the diagnostic accuracy of imaging studies for thoracic sarcoidosis.