D. Minami*a (Dr), N. Takigawab (Prof), Y. Nakajimac (Dr), N. Miyaharac (Prof), Y. Mizumorid (Dr), M. Uedae (Dr), S. Nakamuraf (Mr), F. Suzukif (Mr), Y. Satof (Mr), K. Morikawag (Dr), A. Kanehiroc (Dr)

a Department of Respiratory Medicine, Hosoya Hospital, Ibara City, Okayama, JAPAN ; b Department of Internal Medicine4,Kawasaki Medical School, Okayama, JAPAN ; c Department of Internal Medicine, Himeji Saint Mary's Hospital, Himeji, JAPAN ; d Department of Respiratory Medicine, National Hospital Organization Himeji Medical Center, Himeji, JAPAN ; e Department of Thoracic Surgery, National Hospital Organization Himeji Medical Center, Himeji, JAPAN ; f DNA Chip Research Inc., Tokyo, JAPAN ; g Division of Respiratory Medicine, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, JAPAN

* d-minami@bj8.so-net.ne.jp

Background:Lung cancer compact panel is next-generation sequencing (NGS panels) developed by DNA Chip Research Inc (Tokyo, Japan).The new panel permits sample analysis, including the detection of fusion genes, even when the tumour cell is very low (1%). We report a case with pulmonary invasive mucinous KRAS G12D, diagnosed by samples whose tumor cellcontent was as very low as 2-3%. Case report: A 79-year-old woman with findings of abnormal chest shadows in the left lower lobe, who had presented lumbar spinal canal stenosis, and referred to our hospital. Although endobronchial ultrasound-guided transbronchial biopsy with a guide sheath (EBUS-GS) was tried initially, we could not obtain sufficient specimens for pathological diagnosis because of severe cough and pulmonary bulla adjacent to the tumor. Although brushing cytology was categorized asclass Ⅱ(Papanicolaou classification), the solution was subjected to a new NGS panel research called lung cancer compact panel, because of sufficient EBUS view with EBUS-GS. As a result,KRAS G12D was detectedin the panel research. Therefore, the patient underwent surgery without pathological evidence, and surgical pathology subsequently confirmed the diagnosis of pulmonary invasive mucinous adenocarcinoma. Conclusion: As observed, lung cancer compact panel was efficacy for both detection of KRAS G12D and diagnosis of pulmonary invasive mucinous adenocarcinoma.

Disclosure of funding source(s): none