Miliary lung metastases from non‑small cell lung cancer with Exon 20 insertion: A dismal prognostic entity: A case report

Miliary lung metastases have been reported to be frequently observed in nοn-small cell lung cancer (NSCLC) with major EGFR mutations, which consist of exon 19 deletion and exon 21 L858R. However, it remains undetermined whether NSCLC with minor EGFR mutations possesses characteristics similar to those with major EGFR mutations. In the present study, two cases of miliary lung metastases from NSCLC with exon 20 insertion were reported. Both the patients visited our hospital because of cough and/or dyspnea and were treated with chemotherapeutic agents, including platinum-doublet regimen. In addition, 1 patient received afatinib during the clinical course. However, all therapeutic regimens did not result in the desired outcome, and the respiratory condition rapidly deteriorated. Both the patients succumbed to disease within 3 months from the beginning of the 1st-line treatment due to disease progression. To conclude, chest physicians should be aware that miliary lung metastases could develop in NSCLC patients with exon 20 insertion and present a dismal prognosis.