Non-bacterial thrombotic endocarditis in ROS1-rearranged lung cancer: a report of two cases

Background: Lung cancer is one of the tumor types with highest incidence of thromboembolic events (TE), especially adenocarcinoma subtype. ROS1 rearrangements confer higher risk of TE. Non-bacterial thrombotic endocarditis (NBTE) is a rare event, frequently diagnosed on autopsy. Clinical suspicion is key to reach the diagnosis and start early treatment of the underlying cause and anticoagulation in order to improve patients' outcomes. Case Description: Here we present two cases of NBTE in patients with ROS1-rearranged lung cancer with different clinical debuts. A 42-year-old woman presented initial tetraplegia and impaired level of consciousness, and the other patient, a 54-year-old man, was diagnosed of stroke with sensitive loss of left body. Both were diagnosed of NBTE, confirmed by the finding of cardiac vegetation on echocardiogram and no microorganisms found on blood cultures. Both responded well to targeted therapy with lorlatinib and crizotinib and anticoagulation with heparin. Conclusions: NBTE is an infrequent disease which can cause severe neurological symptoms that impair quality of life, performance status and survival. Early clinical suspicion in patients with higher risk of TEs such as patients with rearrangements of ROS1 gene is of essence. Adequate management of underlying disease and anticoagulation may impact in the recovery of symptoms.