An unexpected cause of a swollen pacemaker pocket: a case report.

To the best of our knowledge, we did not find any earlier reports of a squamous cell carcinoma of the lung spreading to a pacemaker pocket. Presentation of a primary tumour or a metastasis in a pacemaker pocket is extremely rare. Ultrasound imaging with ultrasound-guided biopsy is a fast and reliable method to sample the tissue and to obtain a reliable diagnosis.