Fig. 11

A 68-year-old nonsmoker woman with non-small cell lung cancer, with EGFR exon 19 deletion. Baseline CT of the chest (a) shows multiple lung nodules, which shrunk after 3 months of treatment with the EGFR inhibitor erlotinib (b). While on treatment, patient developed diarrhea, and CT of the abdomen acquired during portal venous phase showed fluid filled large bowel, consistent with drug induced colitis (arrow) (c). After 4 years of treatment, CT of the chest (d) showed a new left lower lobe nodule, which markedly increased in size in 3 months (arrowhead) (e). Biopsy of the nodule showed acquired T90M mutation, which confers resistance to erlotinib. Patient was switched to osimertinib, with initial improvement of the lung nodules on follow-up chest CT (f). Tumor burden remained stable for 2 years, until a chest CT scan showed increased right lower lobe nodule (g). Patient was then switched to pemetrexed