Abstract
RATIONALE: Lipomatous hypertrophy (LH) of the cardiac interatrial septum is a rare benign lesion of the heart, usually described as a nonencapsulated mass arising from the atrial septum, with common symptoms, such as atrial fibrillation, supraventricular tachycardia, and syncope. It is very important to detect LH as early as possible; however, this can be difficult due to the rarity of the condition. PATIENT CONCERNS: Here, we report the unique case of a 60-year-old-man who was found to be unconscious in his car by a paramedic. The patient was declared dead after a preliminary diagnosis of unspecified sudden cardiac arrest. The patient had a history of heart disease and was referred several times by a cardiologist. DIAGNOSES: The final diagnosis of LH was made after autopsy. INTERVENTIONS: Autopsy revealed LH of the cardiac interatrial septum, a soft, smooth mass 12 cm in length, up to 8 cm in width, and weighing 90 g. The interior of the mass was firm, nonelastic, and yellowish in color, with a few vessels. Histological examination confirmed adipose tissue proliferation and perivascular connective tissues between the cardiomyocytes and hypertrophic cardiomyocytes. OUTCOMES: Despite comprehensive examinations, LH was not diagnosed prior to the patient's death, which resulted in a sudden and unexpected fatal outcome. Resuscitation efforts were unsuccessful, and the cause of death was determined postmortem through autopsy. LESSONS: This case highlights the importance of considering LH as a potential etiology of sudden cardiac death, particularly in patients with known cardiac risk factors.