Japanese Society of Internal Medicine Acta Medica Okayama 0918-2918 63 19 2024 A Prompt Diagnosis and Treatment of a Case of Nuclear Protein of the Testis Carcinoma Characterized by a Bronchial Lesion and High Serum Alpha-fetoprotein Level Following Genomic Testing 2655 2660 EN Hiroaki Matsuura Department of Respiratory Medicine, Okayama University Hospital Go Makimoto Department of Respiratory Medicine, Okayama University Hospital Naohiro Oda Department of Respiratory Medicine, Fukuyama City Hospital Kiichiro Ninomiya Center for Comprehensive Genomic Medicine, Okayama University Hospital Hisao Higo Department of Respiratory Medicine, Okayama University Hospital Masanori Fujii Department of Respiratory Medicine, Okayama University Hospital Kammei Rai Center for Innovative Clinical Medicine, Okayama University Hospital Eiki Ichihara Department of Respiratory Medicine, Okayama University Hospital Kadoaki Ohashi Department of Respiratory Medicine, Okayama University Hospital Katsuyuki Hotta Center for Innovative Clinical Medicine, Okayama University Hospital Masahiro Tabata Center for Clinical Oncology, Okayama University Hospital Yoshinobu Maeda Department of Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Nuclear protein of the testis carcinoma (NUTC) is a rare and aggressive malignancy. We herein report a case of NUTC in the lung characterized by a bronchial lesion and elevated alpha-fetoprotein levels. A 35-year-old Japanese man presented to our institution with suspected advanced lung cancer based on a histological examination. Subsequently, next-generation sequencing (NGS) yielded a positive BRD4-NUTM1 fusion. In addition, positive NUT immunostaining of the lung biopsy specimen confirmed NUTC in the lungs. Systemic chemotherapy and radiotherapy showed a temporary response, with decreased serum alpha-fetoprotein levels. We highlight this case of a prompt diagnosis by NGS of NUTC in a young individual with a rapidly progressing tumor. No potential conflict of interest relevant to this article was reported.