A Case of Primary Lung Adenocarcinoma With Two Uncommon Presentations: Neurological Paraneoplastic Syndrome and Pericardial Effusion.

Lung cancer is the second most common cancer worldwide and remains the first cause of cancer death. The diagnosis of lung cancer is mostly made following evaluation for respiratory signs and symptoms but sometimes the first presentation may be atypical. Some symptoms may be related to the invasion of adjacent structures and others caused by an autoimmune-mediated process when cross-reactivity between tumor antigens and normal nervous tissues is responsible for paraneoplastic syndromes. We present a case of a young woman with a smoking history who first manifested with two uncommon presentations of lung cancer: a paraneoplastic neurological syndrome and a hemorrhagic pericardial effusion with cardiac tamponade.