Hodgkin lymphoma as a rare cause of complete atrioventricular block: a case report

INTRODUCTION: Complete atrioventricular block is a life-threatening condition that requires urgent intervention and pacemaker implantation. Determining the underlying cause of the block is essential for effective management. This article describes a rare clinical case of third-degree atrioventricular block caused by Hodgkin lymphoma.

Case Description: On January 14, 2023, an 81-year-old female was urgently admitted to a district hospital with dyspnea, generalized weakness, lower extremity edema, cough, and fever. The rhythm on electrocardiography was interpreted as atrial fibrillation, and chest radiography demonstrated pathologic findings. Pneumonia was diagnosed, and treatment with antibiotics, antiarrhythmic agents, and anticoagulants was initiated. During treatment, sinus rhythm with supraventricular extrasystoles and diffuse myocardial changes was recorded. No clinical improvement was observed. On January 31, 2023, complete atrioventricular block was documented. The patient was urgently transferred to the inpatient cardiology department, where a temporary pacemaker was implanted. Differential diagnosis of the conduction disturbance included drug-induced atrioventricular block and myocardial infarction. Echocardiography revealed masses in the right atrium, thickening of the pericardial leaflets, fluid accumulation in the cavities, and interventricular septal dyskinesia. Computed tomography planned to rule out pulmonary embolism (PE) was not performed because of technical limitations. After 29 hours of hospitalization, the patient died. Postmortem examination revealed Hodgkin lymphoma involving the mediastinum, blood vessels, and all layers of the heart. Thrombotic deposits and tumor emboli containing lymphoma cells were identified in the small branches of the pulmonary arteries. Advanced age, nonspecific symptoms, lack of suspicion for B symptoms, and the rarity of such a cause of atrioventricular block contributed to the delayed diagnosis.

CONCLUSION: Oncologic vigilance among cardiologists regarding patients with atrioventricular block remains low, which may result in diagnostic errors and, in some cases, fatal outcomes. Cardiac involvement may be the first manifestation of mediastinal lymphoma. In the present case, computed tomography might have guided physicians toward the correct diagnosis. This article aims to raise awareness among physicians about lymphomas with cardiac involvement, thereby facilitating earlier diagnosis and more effective treatment.