Mesenchymal‐epithelial transition factor exon 14 skipping mutation‐positive granulocyte colony‐stimulating factor‐producing lung adenocarcinoma mimicking lung abscess: A case report

Abstract

Abstract Granulocyte colony‐stimulating factor (G‐CSF)‐producing lung tumours are rare, with their imaging features and effective treatments remaining elusive. Similarly, mesenchymal‐epithelial transition (MET) exon 14 skipping mutations are also uncommon. Herein, we report a case of G‐CSF‐producing lung adenocarcinoma positive for a MET exon 14 skipping mutation, mimicking lung abscess. A 61‐year‐old man presented with cough and high fever. Contrast‐enhanced chest computed tomography revealed a mass with a cavity and internal fluid accumulation. The patient initially underwent diagnostic treatment for a lung abscess but was ultimately diagnosed with lung adenocarcinoma positive for a MET exon 14 skipping mutation. Following tepotinib therapy, the primary lesion shrank, and serum G‐CSF levels decreased, leading to a diagnosis of G‐CSF‐producing lung cancer. G‐CSF‐producing lung tumours can present imaging findings that mimic lung abscesses. Tepotinib therapy may be effective for patients with MET exon 14 skipping mutation, including those with G‐CSF‐producing lung cancer.

Keywords

• G‐CSF‐producing tumour
• lung abscess
• lung adenocarcinoma
• MET exon 14
• sterile lung abscess
• tepotinib