Unusual Cause of Bradycardia: Cardiac Metastasis From Pancreatic NK/T Cell Lymphoma

Abstract

Extranodal NK/T cell lymphoma (NKTL) is a rare malignancy, accounting for 5-10% of all NHL. A majority of patients with NKTL present with nasal/sinus involvement. About 30% present with extranasal disease involving the upper airway, gastrointestinal tract, lungs, or soft tissues. Cardiac metastasis, in particular, is rare and difficult to diagnose given the lack of symptoms in most cases. Here we present a case of primary pancreatic NKTL with a metastatic right atrial mass. A 34 year-old previously healthy male presented with epigastric pain, jaundice, clay-colored stool, and dark urine for 1 week. He also complained of increasing dyspnea on minimal exertion without chest pain. On exam, he was jaundiced, bradycardic, with epigastric tenderness. Labs showed ALP 907, total bilirubin 10.2, AST 250, ALT 452, and lipase 381. Hepatitis and HIV serologies were negative. EKG showed junctional bradycardia at 42 bpm. CT showed a dilated common bile duct (CBD), pancreatic head and tail masses, and a filling defect in the right atrium. TTE showed a 2x4 cm mass in the right intra-atrial septum. CT guided biopsy of the pancreatic tail mass revealed EBV positive, nasal type NKTL. PET scan revealed hyper-metabolic foci consistent with lymphoma involving the right atrium, pancreas, spleen, and left adrenal gland. ERCP showed a high grade stricture in the distal CBD requiring a sphincterotomy with 2 stents placed in the CBD. The patient was then treated with chemotherapy. Repeat TTE after one cycle showed decrease in the right atrial mass size. Despite that, the patient developed atrial flutter with variable block, which was ultimately controlled with metoprolol. He was subsequently discharged with appropriate follow-up. We presented a rare case of primary pancreatic NKTL with cardiac metastasis. NKTL is a highly aggressive malignancy which rarely involves the heart. Our case emphasizes the point that clinicians should have a high index of suspicion for cardiac metastasis in a patient who presents with a pancreatic mass and cardiac symptoms such as arrhythmias, chest pain or dyspnea. Following the first round of chemotherapy, our patient's arrhythmia evolved to atrial flutter with variable block. This suggests that myocardium infiltrated with lymphoma cells may be susceptible to the development of potentially life-threatening arrhythmias. Thus, particular attention should be made to patients with NKTL and cardiac involvement to avoid arrhythmias post-chemotherapy.