BRAF mutant PD-L1 positive metastatic musculoskeletal lesions from primary lung adenocarcinoma treated with combination vemurafenib and pembrolizumab: a case report.

Background: B-Raf mutation positivity, B-Raf mutation positivity occurrence with programmed death ligand 1 overexpression, and musculoskeletal metastasis are singly rare in non-small cell lung cancer, and even rarer is all occurring in one patient.

Case Presentation: A Filipino 63-year-old male had B-Raf mutation positive and programmed death ligand 1 overexpressed symptomatic metastatic musculoskeletal lesions from lung adenocarcinoma treated with a BRAF inhibitor, vemurafenib, in combination with an immune checkpoint inhibitor, pembrolizumab. He exhibited significant reduction in pain and burden of musculoskeletal metastatic lesions.

Conclusion: Although a rare occurrence and known to have a poor prognosis, B-Raf mutation positive programmed death ligand 1 overexpressed lung adenocarcinoma presenting with metastatic musculoskeletal lesions can respond favorably to a combination immune checkpoint inhibitor and BRAF inhibitor medication.