Interstitial pneumonia with autoimmune features that met the proposed diagnostic criteria for IgG4-related respiratory disease.

We held a multidisciplinary discussion (MDD) about a 61-year-old woman who had an interstitial lung disease (ILD) without extrathoracic lesions that met the classification criteria for interstitial pneumonia with autoimmune features (IPAF) and the proposed diagnostic criteria for immunoglobulin G4 (IgG4)-related respiratory disease (IgG4-RRD). Clinically, the marked progression of lung-limited diffuse lesions was consistent with IPAF. Serum IgG4 and rheumatoid factor levels simultaneously increased and did not contribute to a diagnosis.

Successful erlotinib rechallenge after both gefitinib- and erlotinib-induced interstitial lung diseases.

Epidermal growth factor receptor tyrosine kinase inhibitors, gefitnib and erlotinib, are effective for advanced nonsmall-cell lung cancer with epidermal growth factor receptor gene mutation. However, interstitial lung disease induced by these drugs is sometimes fatal, and discontinuation of the medication is the principle approach once this occurs. There are, however, some reports of cases in which rechallenge of gefitinib or erlotinib was successful, and it remains unclear when or how rechallenge should be attempted.