Epidermal growth factor receptor (EGFR) mutation testing is useful for primary lung cancer diagnosis and appropriate...

Primary lung cancer was suspected in three patients upon chest computed tomography (CT) and bronchoscopy. Wash cytology revealed that all patients had lesions categorized as class III or lower (Papanicolaou classification), and the wash solution was then subjected to an epidermal growth factor receptor (EGFR) mutation search. As a result, exon 19 deletion was found in two patients, whereas an exon 21 L858R mutation was found in one. Therefore, all three patients underwent surgery without pathological evidence, and surgical pathology subsequently confirmed the diagnosis of primary lung adenocarcinoma. As observed, EGFR mutation testing was useful for cancer diagnosis.