Ischaemic Stroke as a Manifestation of Marantic Endocarditis in Lung Adenocarcinoma.

Marantic endocarditis (ME) is characterised by the formation of sterile valvular vegetations, carrying a high risk of systemic embolism. It is frequently associated with advanced neoplasms, particularly adenocarcinomas of the lung. Osimertinib, often used in lung adenocarcinomas, is linked with thrombocytopenia. We report the case of a 57-year-old female with stage IV lung adenocarcinoma on osimertinib, who presented with acute neurological deficits due to an M2 segment occlusion of the left middle cerebral artery, which was treated with mechanical thrombectomy. The post-procedure course was marked by haemorrhagic transformation and systemic embolic events, including splenic ischaemia and the appearance of Janeway lesions. Transthoracic echocardiography identified mitral valve vegetations which, in the context of negative blood cultures and multiple embolic phenomena, made the picture of ME highly suggestive. Due to significant haemorrhagic risk, given the severe thrombocytopenia and haemorrhagic transformation, therapeutic anticoagulation was not feasible. The patient's clinical state deteriorated rapidly following deep vein thrombosis and pulmonary embolism, culminating in multiorgan failure and death. In this complex case, therapeutic strategy was limited by important thrombocytopenia and the haemorrhagic risk associated with stroke, precluding anticoagulation - a cornerstone of treatment for ME -and thereby affecting the patient's prognosis.