What happened, in summary

A 30-year-old woman who had never smoked was diagnosed with Stage III lung adenocarcinoma after imaging showed a right upper-lung nodule and extensive chest and neck lymph-node involvement. Her tumor had very high PD-L1 expression. She began pembrolizumab, but after an early period of apparent shrinkage the cancer progressed, with worsening lymph-node disease and pleural involvement confirmed on biopsy. Radiation was used to relieve neck pain and facial swelling. Broader molecular testing then identified a BRAF V600E mutation. She switched to dabrafenib plus trametinib. The pleural effusion stopped and the enlarged lymph nodes shrank markedly. Fever, liver-test abnormalities and erythema nodosum developed during treatment but improved with temporary steroids. At the time of publication, more than 5 years had passed since her first visit, targeted therapy was still working, and follow-up imaging showed no trend toward cancer progression.