A 52-year-old woman developed sudden dyspnea without fever. Seven months earlier, she underwent breast-conserving surgery for right metaplastic carcinoma (pT1bN0M0) and received adjuvant paclitaxel plus trastuzumab, followed by trastuzumab with radiotherapy (40 Gy/15 fractions; Fig. 1A). Chest CT showed right upper lobe consolidation with air bronchograms extending beyond the radiation field, with metallic clips at the lumpectomy site (Fig. 1B), and multifocal ground-glass opacities in the same lobe (Fig. 1C). Complete blood count was unremarkable. Bronchoalveolar lavage cytology was negative for malignancy, and cultures/special stains excluded fungi and acid-fast bacilli. Based on the radiotherapy history, interval, and imaging findings, radiation-induced organizing pneumonia (RIOP) was diagnosed. Prednisolone 30 mg/day resulted in symptom resolution and radiographic improvement. RIOP typically develops several months after radiotherapy and is characterized by migratory, multifocal opacities that may extend beyond the irradiated field, distinguishing it from radiation pneumonitis or radiation recall pneumonitis (1,2,3).
Fig. 1.
Footnotes
- Conceptualization, K.S.H.
- data curation, K.S.H.
- supervision, J.J.I.
- writing—original draft, K.S.H.
- writing—review & editing, all authors.
Conflicts of Interest: Sung Hun Kim has been a Editor-in-Chief of the Journal of the Korean Society of Radiology since 2024; however, she was not involved in the peer reviewer selection, evaluation, or decision process of this article. Otherwise, no other potential conflicts of interest relevant to this article were reported. The remaining author declares no conflicts of interest.
Funding: None
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