Radiographic and CT features of radiation-induced organizing pneumonia syndrome after breast-conserving therapy

Purpose To investigate radiographic and computed tomography features of radiation-induced organizing pneumonia syndrome after breast-conserving surgery. Materials and methods The appearances and distribution of lung parenchymal abnormalities were retrospectively analyzed on chest radiographs ( n = 12) and computed tomography scan images ( n = 10) of 12 women (range 37–78 years, mean 55.8 years) with radiation-induced organizing pneumonia syndrome after breast-conserving surgery. Results The principal radiographic feature was an airspace filling pattern in all patients that involved the middle and lower lung zones in 10 of the 12 patients. Multi-focal lesions manifesting airspace consolidation surrounded by ground-glass opacities were the predominant CT finding in all 10 of these patients. The main lesion was predominantly located in the lung periphery in nine patients and contiguously extended to the central portion of the lung in seven patients. Frequent ancillary findings were airway dilation within the consolidation and lobar volume loss in nine and eight patients, respectively. All had solitary (6/10) or multifocal (4/10) distant lung opacities, mostly consistent with the finding of ground-glass opacities (9/10). Migration of the lung disease was observed in ten patients on subsequent radiographs. Conclusion The cardinal radiologic feature of this syndrome is airspace consolidation surrounded by ground-glass opacification with airway dilation and volume loss, involving primarily the irradiated, subpleural area, along with distant opacities.