Lipomatous hypertrophy of cardiac interatrial septum: A case report

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.

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.

The final diagnosis of LH was made after autopsy.

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.

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.

This case highlights the importance of considering LH as a potential etiology of sudden cardiac death, particularly in patients with known cardiac risk factors.