Abstract Pulmonary hemorrhage is a severe complication characterized by massive bleeding into the lungs, often resulting from vascular erosion or rupture. It is associated with advanced non-small cell lung cancer (NSCLC), particularly in cases with tumor cavitation, necrosis, and recent radiotherapy. The emergence of immune checkpoint inhibitors (ICIs), such as pembrolizumab, has transformed the treatment landscape of NSCLC. While effective, ICIs can increase hemorrhage risk through immune-mediated tumor necrosis and inflammation. A 60-year-old male with a with a medical history of chronic obstructive pulmonary disease and PD-L1 positive stage IV NSCLC with brain and abdominal metastases, currently receiving palliative pembrolizumab therapy presented with shortness of breath and hemoptysis. On admission he had a heart rate of 110bpm, respiratory rate of 40bpm, and requiring 4L of oxygen via nasal canula to maintain oxygen saturation above 90%. Laboratory findings revealed elevated lactic acid (2.1 mmol/L), leukocytosis (WBC count of 17.1 × 109/L), and a hemoglobin level of 15.7 g/dL. A whole-body CT scan identified a known endobronchial mass at the level of the right mainstem bronchus, now exhibiting erosion through the bronchial wall and active extravasation involving the right pulmonary artery. The patient subsequently required intubation and mechanical ventilation. Bedside bronchoscopy revealed a large blood clot in the proximal right upper lobe, which was suctioned to expose necrosis and erosion of the posterior bronchial wall. Advancement of the bronchoscope was not possible beyond this point. The patient was admitted to the ICU, where a cardiothoracic surgeon and an interventional radiologist assessed the case. Given extent of invasion and hemorrhaging, it was determined inoperable. The patient was ultimately transitioned to comfort care measures and subsequently passed away on same day of admission. While pulmonary hemorrhage is a known risk in NSCLC, its association with pembrolizumab is relatively rare. Diffuse alveolar hemorrhage in the setting of pembrolizumab-associated interstitial lung disease and pembrolizumab-associated impaired wound healing leading to lung erosion has been scarcely reported in literature. This is the first case describing lung erosion with extravasation into a pulmonary artery associate to pembrolizumab. The pathophysiology of immunotherapy-mediated pulmonary hemorrhage is not fully understood but may involve immune-related inflammation leading to increased vascular permeability and subsequent hemorrhage. This case highlights a rare complication of pembrolizumab therapy in a patient with advanced PD-L1 positive. Our findings suggest that immune-mediated inflammation and impaired tissue healing may contribute to vascular erosion and catastrophic bleeding. This abstract is funded by: None
Silva et al. (Fri,) studied this question.