Po-01-107 intra-cardiac spindle cell carcinoma following catheter ablation of atrial fibrillation and left atrial appendage closure

Spindle cell carcinoma (SpCC), a type of squamous cell carcinoma (SCC), is a rare tumor with features similar to sarcoma that often arises from the respiratory system. Myocardial involvement of these tumors has not been described. We present a case of metastatic SpCC diagnosed through routine transesophageal echocardiography (TEE) following left atrial appendage occlusion (LAAO). To describe a rare occurrence of metastatic SpCC diagnosed through routine TEE following LAA occlusion. NA A 61 year old male with a history of coronary artery disease and heart failure presented with persistent symptomatic atrial fibrillation (AF) despite anti-arrhythmic therapy. We performed pulmonary vein isolation (PVI) and during intubation a laryngeal mass was noted. He was diagnosed with T2N0M0 sarcomatoid SCC and had surgery, radiation and chemotherapy (cisplatin). At that time, he was felt to have a favorable 5 year survival prognosis. Six months later he represented with symptomatic AF and underwent repeat PVI. Due to concerns regarding bleeding risk, LAAO was later performed. During follow up TEE at day 45, a new cystic lesion arising from the posterior left atrium and a 2x3cm heterogenous mass associated with the interatrial septum was noted (Figure 1 A-D). CT scan showed new mediastinal masses with extension into the left atrium in the region treated with radiofrequency ablation (Figure 1 E-H). Biopsy revealed SpCC consistent with the initial laryngeal mass. Tumor extending from the perihilar mass and in the fossa ovalis, given the proximity of prior work and prior transseptal puncture, raises the concern for inadvertent iatrogenic spread of tumor and that catheter manipulation facilitated invasion into the LA with the pedunculated mass and seeded the septum. The patient unfortunately continued to decline clinically and shortly thereafter transitioned to comfort care and passed away. We present a case of persistent symptomatic AF in which laryngeal SpCC was diagnosed during initial PVI and rapidly progressive metastatic SpCC diagnosed via TEE in follow up after LAAO. This presentation is concerning for inadvertent iatrogenic spread of tumor from an extracardiac source through PVI. SpCC is more aggressive than typical SCC, however rapid invasion through the chest wall, lung and myocardium within 1.5 months is extremely rare. While primary spindle cell sarcoma of the myocardium has been reported, to our knowledge we report the first case of metastatic SpCC to the heart.