Pulmonary Arterial Hypertension in a Patient With Metastatic Lung Cancer on Pembrolizumab: Whom to Blame?

Immune checkpoint inhibitors (ICIs) play a major role in current cancer treatments. They are associated with immune-mediated side effects due to immune dysregulation. ICI-mediated complications are more commonly known to affect thyroid gland, gastrointestinal system, skin, etc. Pulmonary arterial hypertension (PAH) due to ICIs is not very well described in the literature. Here, we report a case of severe PAH diagnosed in a patient with metastatic lung cancer on long-term pembrolizumab and literature review.