Saprochaete capitata superinfection mimicking steroid-refractory radiation pneumonitis after SBRT for oligometastatic lung lesion: A case report and literature review

Vollständiger Abstract

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Objective: Radiation pneumonitis (RP) is a well-recognized pulmonary complication of stereotactic body radiotherapy (SBRT). However, opportunistic fungal superinfection complicating RP remains exceedingly rare. This case report highlights the diagnostic challenges and clinical management considerations of a rare fungal superinfection that closely mimics steroid-refractory RP. Case Presentation: A 62-year-old man with locally advanced non-small cell lung cancer (NSCLC) developed Grade 2 RP after receiving stereotactic body radiotherapy (SBRT) for a solitary oligometastatic pulmonary nodule following concurrent chemoradiotherapy. Initial treatment with high-dose systemic corticosteroids failed to improve clinical status. Subsequent evaluation, including a positive serum galactomannan assay and sputum culture, identified a secondary Saprochaete capitata infection. Voriconazole therapy led to rapid symptomatic and radiographic resolution. Conclusions: In patients with RP who fail to respond to corticosteroids, particularly those with prolonged immunosuppressive exposure, clinicians should maintain a high index of suspicion for secondary fungal infections. Prompt diagnostic evaluation—including serial galactomannan assays, procalcitonin testing, and sputum cultures—along with early initiation of targeted antifungal therapy, is essential to reduce morbidity and mortality in this high-risk population.