Transient asymptomatic pulmonary opacities in a patient with MET exon 14 skipping non-small cell lung cancer: A case report.

Mesenchymal epithelial transition factor receptor (MET) tyrosine kinase inhibitors (MET-TKIs) have been approved for the treatment of non-small cell lung cancers with MET exon 14 skipping mutations. Transient asymptomatic pulmonary opacities (TAPOs) associated with epidermal growth factor receptor (EGFR)-TKIs have been reported. Here, we report a case wherein ground-glass opacities (GGOs) appeared during the course of treatment with tepotinib, a MET-TKI, but spontaneously resolved with drug withdrawal, after which treatment was resumed with a reduced dose. Although there have been no reports of TAPOs with MET-TKIs, the clinical and imaging findings of this case were consistent with TAPOs. For TAPOs occurring because of MET-TKI, the drug can be continued under careful observation even if GGOs appear.