Isolated pericardial hydatid cyst: a case report

Introduction and importance:

Hydatid cysts are most commonly found in the liver and lungs but rarely in the heart. Most heart hydatid cysts are located in the left ventricle and the interventricular septum. Few cases of isolated pericardial hydatid cysts have been reported in the literature. Cardiac involvement can have serious consequences and can be fatal if the cyst perforates. Methods for diagnosing cardiac hydatid cysts include serological tests and noninvasive imaging tests such as transthoracic echocardiography, computed tomography, and magnetic resonance imagery.

Case presentation:

Here we report a rare case of an isolated pericardial hydatid cyst in a young woman who complained of sternal chest pain, palpitations, and shortness of breath. The diagnosis of pericardial hydatic cyst in our case was confirmed by serologic tests for hydatidosis and the results of echocardiography and tomography. No other localizations were found after realizing a body scan. The patient was started on oral albendazole and then was referred to surgery for the resection of the cardiac mass.

Conclusion:

Cardiac hydatid cyst represents a rare disease, frequently associated with fatal complications, which makes its early diagnosis and treatment an urgent priority.

Introduction

Highlights

• Pericardial localization without myocardial involvement is extremely uncommon.

• Patients with a cardiac hydatid cyst may remain asymptomatic for many years. However, lethal complications have been reported, such as cyst rupture leading to cardiac tamponade, anaphylaxis, death, cardiac compression, and atrial fibrillation.

• The diagnosis is based on transthoracic echocardiography, followed by computed tomography, MRI, and serological tests.

• The recommended treatment is excision of the cyst because of the possibility of severe complications.

A hydatid cyst is a parasitic infection that is caused by the larval stage of Echinococcus granulosus. It is usually found in the liver and lungs. Cardiac involvement is fairly rare. The incidence of cardiogenic echinococcosis is less than 2% of the total echinococcosis incidence, even in countries where echinococcosis is endemic1. The left ventricle and interventricular septum represent the main cardiac hydatid cysts localizations. Pericardial localization without myocardial involvement is also very rare2. Patients with cardiac hydatic cysts may remain asymptomatic for years or exhibit mild, nonspecific symptoms. However, fatal complications have been reported in the literature, such as cardiac compression, atrial fibrillation, and cyst rupture leading to cardiac tamponade, anaphylaxis, or even death3,4. Herein, we report a rare case of an isolated pericardial hydatid cyst in a 48-year-old woman who presented to the emergency department with chest pain, palpitations, and shortness of breath.

This case has been reported in line with the 2020 SCARE (Surgical CAse REport) guidelines5.

Case report

A 48-year-old woman presented to the emergency department with acute chest pain, shortness of breath, palpitations, and fever for the last 3–4 days. She had no history of trauma or major illness and had no contact with animals. She had no allergies, no drug history, was never operated on before, and had no family history. On her physical examination, she had a temperature of 39°C, her arterial blood pressure was 134/86 mmHg, her heart rate was 112 beats per minute, her SpO₂ at 97% on room air, and her respiratory rate was 20 breaths per minute. On auscultation, the chest was clear, and heart sounds were normal with no cardiac murmur. No jugular venous distention or gallop rhythm was noted. Electrocardiography showed sinus tachycardia. Chest X-ray revealed the presence of multiple opacities with calcified contours localized on laterotracheal and left paraventricular areas with the interstitial syndrome (Fig. 1).

Figure 1.

Chest X-ray showing opacities with calcified contours on left heart borders.

Transthoracic echocardiographic examination illustrated normal cardiac structures and function with a cystic mass lesion located in the pericardium adjacent to the left ventricle without any pressure effect (Fig. 2).

Figure 2.

Subcostal echocardiography view showing a cystic pericardial mass.

Her thoracic computed tomography (CT) showed the appearance of infectious pleuropneumonia and the presence of a low-density formation with a pericardial calcified wall next to the emergence of the pulmonary artery trunk measuring 60×54×53 mm and another low-density pseudocystic lesion under the bronchial carina with calcified borders measuring 70×76×22 mm (Figs 3 and 4).

Figure 3.

Axial computed tomography scan of the thorax showing hydatid cyst in the pericardium.

Figure 4.

Thoracic computed scan reconstruction showing solitary cystic lesion on the left side of the pericardium.

Results of serologic tests for hydatidosis were positive for E. granulosus, and marked eosinophilia at 26% was present too.

A body scan was realized to search for other localizations, but no cysts were detected in the liver, lungs, or brain.

In light of these findings, the diagnosis of cardiac Echinococcosis associated with infectious pleuropneumonia was done, and the patient was started on oral albendazole (200 mg/twice a day) with dual antibiotic therapy with good evolution. Thereafter, surgical resection of the cardiac mass was planned and the patient was referred, after her consenting, to the cardiovascular surgery department.

Discussion

Hydatid cyst is a parasitic disease caused by tapeworms of the genus E. granulosus. The liver, followed by the lung, is the most common site of involvement. The incidence of synchronous liver and lung hydatidosis varies between 5.8 and 13.3%6.

This infection is endemic in subtropical and tropical regions such as the Mediterranean, Africa, Australia, the Middle East, and South America. Humans become infected with the intermediate stage of the parasite by consuming egg-contaminated water or food or by direct contact with infected dogs. Once parasites cross the intestinal wall and reach the portal or lymphatic system, the liver is the most commonly affected organ (70%), as it acts as the first line of defense7,8. The lung is the second most common site of involvement (20%). Cardiac primary echinococcosis is rare and has been reported to account for 0.02–2% of all hydatid cyst sites2. The most common sites of cardiac involvement were the interventricular septum in 46% of cases, followed by the right atrium in 15.3% of cases, the left ventricular free wall in 15.3%, the pericardium in 7.7%, the right ventricular free wall in 7.7%, and the left atrium in the last with 7.7%2. Pericardial lesions occur primarily in poly-cardiac echinococcus. The solitary pericardial hydatic cyst is a rare presentation of this disease which was observed in our case.

Cardiac involvement occurs primarily by myocardial infiltration from the coronary arteries. A second involvement is through pulmonary veins secondary to pulmonary echinococcal cysts rupture9. Hydatic cysts are more common in the left ventricle due to left coronary artery predominance10. Right ventricular hydatid cysts differ from left ventricular ones. In the right ventricle, cysts enlarge in the ventricular and subendocardial spaces and, thus, are prone to rupture and can lead to pulmonary embolism, anaphylaxis, and sudden death. At the same time, the left ventricular hydatid cysts grow as subepicardial masses and rarely rupture in the pericardial space11,12.

Clinical manifestations of cardiac echinococcosis depend on the size and location of the cyst. In the early stages of the disease, it may be asymptomatic and discovered incidentally. Nonspecific symptoms such as chest pain, dyspnea, persistent cough, palpitations, arrhythmias, and heart failure are likely reported2–13. In this case, the disease was manifested by chest pain, shortness of breath, and palpitations.

The most serious complication of pericardial cysts is perforation, with an incidence of 25–40%13. Cyst rupture into the bloodstream leads to aphylactic shock. Other complications may be seen and include systemic or pulmonary hydatic embolism, mitral regurgitation secondary to papillary muscle involvement, valve obstruction, atrioventricular conduction abnormalities, and arrhythmias. Symptoms of pericardial cysts are usually due to pressure on the heart muscle from an expanding or ruptured cyst. The rupture of a hydatid cyst into the pericardial space can cause pericarditis with effusion, cardiac tamponade, and secondary cyst formation4,14.

Diagnosis is based on cardiac imaging techniques such as echocardiography, CT, and magnetic resonance imaging, in addition to serological tests8.

Transthoracic echocardiography (TTE) is widely available, noninvasive, easy to perform, and highly sensitive in identifying intracardiac hydatid cysts and planning surgical interventions15. Although cardiac hydatid cysts are uncommon, some authors recommend routine TTE screening in the case of liver or lung hydatid cysts16,17.

Round, thin-walled, multilocular masses on ultrasound are characteristic of echinococcal cysts8. A hydatid cyst should always be considered in an intracardiac cyst image. However, the echo lucent and multiseptal nature of hydatid cysts may be absent, and they may appear as tumor-like masses8,15. On radiographic imaging, the specific findings of hydatic cysts are calcification of the cyst wall, the presence of daughter cysts, and membrane detachment. Although CT has been reported to be the best imaging modality to show wall calcification, the anatomical proximity of hydatid cysts, the state of the cyst structure, and the precise anatomic location are best shown by MRI18,19. Images obtained with the cine gradient echo technique not only provide morphological information about cardiac cysts but also show the impact of cysts on cardiac function16.

Serological tests – the Casoni test – are not very reliable. ELISA (enzyme-linked immunosorbent assay) tests have higher sensitivity and specificity2.

The recommended treatment for cardiac hydatic cysts is based on the excision of the cyst, even if patients are asymptomatic, since they can have serious complications such as cyst rupture and sudden death4,6,20.

Preoperative treatment with albendazole begins at least 3 months to 1 day before surgery and continues for 1–3 months after treatment. The WHO recommends that even asymptomatic patients with operable disease should undergo surgical removal of the cyst followed by medical therapy for at least 2 years. With the chronic use of albendazole, great attention must be paid to liver enzymes. Serological and echocardiographic monitoring for 5 years after surgery is recommended to rule out recurrence2.

Conclusion

Cardiac hydatid cyst is a rare disease that is frequently associated with fatal complications, making its early diagnosis and treatment an urgent priority. The diagnosis is based essentially on TTE data followed by CT, MRI, and serology. Surgical excision is the best treatment for cardiac hydatid cysts located in the pericardium.

Ethical approval

The study was exempt from ethical approval in our institution.

Consent

Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Sources of funding

The authors declared that this study had received no financial support.

Author contribution

I.T.: corresponding author, data collection, and writing the paper; F.K.: writing the paper; H.R.: data collection; A.E.: contributor; R.H.: contributor. This work was carried out in collaboration with all the authors who have read and approved the final manuscript.

Conflicts of interest disclosure

The authors declare having no conflicts of interest in this article.

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Imane Tlohi.

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