Large isolated hydatid cyst of the interventricular septum

Abstract

A 54-year-old woman was referred to our echocardiography clinic for long-standing hypertension. She did not have any chest pain, dyspnoea, fever or weight loss. She was on losartan of dose 25 mg twice daily. She did not have history of contact with livestock or pet animals. Electrocardiogram showed T-wave inversion in V1-V3 leads. On transthoracic echocardiography, there was a large mass in the interventricular septum (Fig. 1, Videos 1 and 2). Computerised tomography (CT) of the chest showed a cystic mass (85×65 mm) over the interventricular septum with a rim-like calcification of its wall consistent with cardiac hydatid cyst (Fig. 2). The lungs appeared normal and free of disease. CT images of the brain and the abdomen were otherwise normal with no cerebral or hepatic involvement. The patient underwent surgery and pathological examination was consistent with echinococcal hydatid cyst (Fig. 3). She made full recovery following surgery (Video 3). Hydatidosis most frequently involves the lungs and the liver though it can potentially occur in any tissue (1). Cardiac involvement is seen in 0.02-2.0% of patients with hydatidosis. Echinococcal seeding of the myocardium occurs either through arterial or through venous circulation (1). Interventricular septum involvement accounts for 4% of cardiac cases (1, 2). In more than half of the cases, heart is not the only involved organ (3). Symptoms of cardiac hydatid cyst depend on the age, size, location and involvement of neighbouring structures (1). Cardiac hydatid cysts are typically asymptomatic with only 10% of patients having symptoms at earlier stages (2). Approximately 10% of the cardiac cysts remain asymptomatic for many years, the remaining generally become symptomatic as the disease progresses (3). Chest pain is the most commonly reported symptom followed by palpitations, cough and dyspnoea (3). They can present with symptoms of valvular dysfunction, various conduction disturbances (in those with interventricular septum involvement or even cardiac tamponade (secondary to the rupture of the cyst) and sudden cardiac death (3). In the presented case, subtle electrocardiographic findings prompted further work up which lead to the diagnosis, though the patient did not report symptoms related to the large cyst. Surgical excision is the definitive treatment and it is recommended even in asymptomatic patients due to the seriousness of the complications following spontaneous rupture of the cysts (3). Surgery generally yields complete recovery and the prognosis is excellent (4).