EGFR-Mutant Lung Adenocarcinoma With Bone and Leptomeningeal Metastases

What happened, in summary

A 42-year-old man initially sought care in July 2020 for sudden right-sided chest pain. Imaging showed inflammation, multiple lung nodules, pleural changes, and enlarged mediastinal lymph nodes. During the admission he developed extensive neck-vein thrombosis and septic pulmonary emboli and was diagnosed with Lemierre syndrome. After treatment for the infection and thrombosis, persistent lung abnormalities prompted further investigation. PET-CT and a supraclavicular lymph-node biopsy in August 2020 confirmed metastatic lung adenocarcinoma with bone metastases, making this Stage IV disease. Molecular testing found an EGFR exon 19 deletion, and he began afatinib with a partial response. When an acquired EGFR T790M resistance mutation appeared in 2021, he switched to osimertinib and maintained a partial response. In 2024, new headaches led to MRI and cerebrospinal-fluid testing that confirmed leptomeningeal metastases. Treatment changed to furmonertinib. After further central-nervous-system progression later that year, pemetrexed, carboplatin, and bevacizumab were added while furmonertinib continued; carboplatin was later discontinued. By May 2025, leptomeningeal disease was still visible and cancer cells remained detectable in cerebrospinal fluid. He received cycles 7 and 8 of pemetrexed and bevacizumab with a higher furmonertinib dose and was discharged in stable condition, with occasional headaches but no major respiratory or gastrointestinal symptoms.