Atrial fibrillation and atrial flutter are atrial tachycardias associated with embolic strokes. To date, there have only been a few reports highlighting the incidence of these atrial tachycardias due to mechanical compression of myocardial structures and the pulmonary vasculature in certain mediastinal masses and cysts.

We present a case of a 75-year-old gentleman who is a nonsmoker with a history of hypertension who presents with an acute embolic stroke due to atrial flutter likely from mechanical compression from an underlying squamous cell carcinoma of the lung.

This case represents, to the best of our knowledge, a rare case of squamous cell carcinoma of the lung in a nonsmoker likely leading to mechanical compression and a resultant atrial tachycardia with an embolic stroke.