New-onset acute interstitial lung disease after treatment with erlotinib in a patient with metastatic squamous cell carcinoma of the lung.

Erlotinib is a Human Epidermal Growth Factor Receptor Type 1/tyrosine kinase (EGFR) inhibitor, which is used for non-small-cell lung cancer treatment. Erlotinib usually has a favorable safety profile however; adverse events such as interstitial lung disease (ILD) have been reported in pivotal studies. ILD usually occurs weeks to months after initiating therapy with Erlotinib. We report a case of Erlotinib induced ILD presenting within 5 days of initiating treatment with Erlotinib.