Multimodal imaging for the diagnosis of cardiac alveolar echinococcosis: a case report

doi:10.21203/rs.3.rs-4959365/v1

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Case Report

Multimodal imaging for the diagnosis of cardiac alveolar echinococcosis: a case report

https://doi.org/10.21203/rs.3.rs-4959365/v1

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Background: Primary cardiac echinococcosis is rare, and cardiac alveolar echinococcosis is even rarer and more unusual. Reported cases of this disease are extremely limited, and multimodal imaging provides an important guide to treatment and decision-making. We report a case of cardiac alveolar echinococcosis.

Case summary: A 31-year-old male patient with no specific medical history was found to have a cardiac space-occupying lesion on physical examination one day earlier. Transthoracic echocardiography showed a cystic mass anterior to the right lateral aspect of the right atrium, which did not show enhancement on the enhanced scan. Multidetector computed tomography and cardiac magnetic resonance showed a cystic space-occupying lesion in the right lateral aspect of the right atrium, with mild enhancement of the edges of the lesion and multiple small vesicles on the enhancement scan. Surgery was performed on suspicion of cardiac alveolar echinococcosis, and the lesion was successfully excised. Ultimately, postoperative histopathologic examination revealed cardiac alveolar echinococcosis. The patient recovered well and was discharged with regular postoperative oral albendazole tablets and regular follow-up reviews.

Conclusion: We report a case of cardiac alveolar echinococcosis with multimodal imaging features and therapeutic strategies, an extremely rare cardiac occupying disease. Multimodal imaging can be very helpful in diagnosing the disease; however, surgical resection with histopathologic diagnosis is essential. Appropriate postoperative treatment and follow-up are based on histologic findings. This rare case emphasizes the integrated diagnosis of cardiac alveolar echinococcosis with clinical, multimodal imaging and pathologic data.

cardiac alveolar echinococcosis

multimodal imaging

case report

Echinococcosis is a chronic disease caused by larval infection of echinococcus tapeworms of the genus Echinococcus. The two main types of echinococcus tapeworms that can infect humans in the larval stage are Echinococcus granulosus and Echinococcus multilocularis, which cause cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively[1]. CE is more common, while AE is rarer, accounting for only 1-2% of cases of echinococcosis[2]. This disease is more prevalent in the liver and lungs, and cardiac echinococcosis is extremely rare, accounting for only 0.5%- 2.0% of cases[3]. Echocardiography, MDCT, and CMR can show the lesion's relationship to the heart chambers. Here, we report a case of primary cardiac alveolar echinococcosis confirmed by pathologic examination of surgical specimens.

A 31-year-old male presented to our Cardiovascular Surgery Department on 05/2024 with the chief complaint of a cardiac space-occupying lesion detected on physical examination one day earlier. He denied any family history of hypertension, diabetes mellitus, dyslipidemia, smoking, or atherosclerotic disease. His vital signs were blood pressure 120/70 mmHg, heart rate 80 beats/min, respiration 20 beats/min, and body temperature 36.7°C. Physical examination showed no murmur or pericardial friction in the precordial region, and normal electrocardiogram and chest radiographs showed no active lesions in the lungs. Laboratory tests suggested that the patient’s hydatid serological IgG ELISA was positive. Liver insufficiency and positive HBsAg, HBeAg, and HBcAb tests for hepatitis B; the rest of the laboratory tests showed no significant abnormalities.

Transthoracic echocardiography showed that a cystic mass of about 6.6×5.8 cm in size was seen in front of the right lateral aspect of the right atrium, with a thicker, double-layered wall, and a fine light spot echo was seen in it. There was a clear demarcation between the lesion and the diaphragm, and the lesion compressed the inferior vena cava and localized it to become thin. Ultrasound contrast examination showed no significant enhancement of the lesion in the arterial phase, portal phase, and delayed phase, and the lesion boundary was clear (Fig. 1A-B). MDCT showed an increased volume of the right atrium and cystic hypodense occupations with varying thicknesses of the sac wall. Columnar slightly hyperdense shadow in the bronchial walking area in the posterior segment of the upper lobe of the left lung, considering the possibility of endobronchial mucus plug formation (Fig. 2A). Computed tomography angiography (CTA)of the thoracic aorta showed a cystic hypodense lesion in the inferior lateral aspect of the right atrium, with a measured maximum cross-sectional area of approximately 7.4 x 6.7 x 6.4 cm and an internal CT value of approximately 15 HU. Enhancement scans showed mild enhancement at the edges of the lesion, with small cystic hypodense shadows seen in the periphery (Fig. 2B). The lower edge of the lesion was poorly demarcated from the liver parenchyma, and there was marked compression of the inferior vena cava and right atrium. CMR examination showed a cystic mass lesion on the right outer side of the right atrium, which showed a slightly low signal on T1-weighted imaging (T1WI) and a high signal on T2-weighted imaging (T2WI). Multiple small vesicles at the edge of the lesion showed a higher signal on T2WI (Fig. 3A-C). Early first-pass perfusion MRI showed no signs of perfusion inside the lesion (Fig. 3D). Enhanced scanning shows delayed enhancement of the lesion edge, compression of the right atrium and local right ventricle, compression of the hepatic segment of the inferior vena cava, and unclear boundary with the lesion; Mild mitral and tricuspid regurgitation (Fig. 3E). After the above examination, the clinical doctor considered that the patient's disease was cardiac alveolar echinococcosis and could not rule out a pericardial cyst. Therefore, the patient underwent thoracoscopic assisted resection of pericardial echinococcosis lesions.

Intraoperatively, a 6 cm × 8 cm-sized mass in the right mediastinum was observed, which was tough and closely related to the pericardium and diaphragm, with noticeable compression of the right atrium and inferior vena cava. Under the guidance of extracorporeal circulation, the tumour was punctured, and milky yellow pus was withdrawn; the mass was dissected longitudinally, about 50 ml of pus was left in the mass, necrotic tissues and pus moss were seen in the lumen, and the wall of the tumour was irregular, the pus was aspirated, the pus moss was removed, and the wall of the tumour and part of the pericardium was removed. Intraoperatively, a 6 cm × 8 cm-sized mass in the right mediastinum was observed, which was tough and closely related to the pericardium and diaphragm, with noticeable compression of the right atrium and inferior vena cava. In the pathological examination, necrosis and acute and chronic inflammatory cell infiltration were seen in the tissue sent for examination. A few powder-stained unstructured materials were also seen, which were mostly considered as echinococcosis, and ultimately, the frozen section tumour was diagnosed as cardiac alveolar echinococcosis (Fig. 4A-B).

On follow-up MDCT of the chest one week after surgery, the cardiac mass showed post-resection changes, blurred and exudative fat interstitial space in the operated area, and poorly demarcated locally from the adjacent liver lobes; there is a small amount of fluid accumulation in the right chest cavity, and adjacent lung tissue is compressed and not fully expanded; multiple flocculent exudates and ground-glass nodular hyperdense shadows in the right lobe of the lung are considered to be infections, and follow-up is recommended. The patient recovered from the operation, was very satisfied with the treatment received, and was discharged two weeks later. The patient was instructed to have regular follow-ups to monitor the regression of the disease and to take regular oral albendazole tablets 15 mg/(kg.d) in 2 divided doses (after breakfast and dinner). Periodically (1 month) review liver and kidney function, blood counts, and coagulation combinations. Review CT every six months.

AE, also known as multilocular echinococcosis, is a specific type of echinococcosis. This rare zoonotic parasitic disease has been reported throughout the world, mainly in the northern hemisphere, with epidemics throughout much of Europe, northern Asia, and North America[4-6]. Intact intramyocardial single encapsulated cysts less than 1 cm in diameter rarely cause signs and symptoms so that infected patients may remain asymptomatic for many years. Secondary cardiac echinococcosis is usually detected after diagnosis of echinococcosis in other organs on systemic examination[7]. This case is a primary cardiac alveolar echinococcosis.Symptoms of cardiac echinococcosis are related to several factors, such as the location of the cyst, the number of cysts or fistula formation. When the encapsulated cysts in the heart muscle grow large, symptoms such as shortness of breath, palpitations, and fever may occur[8]. Potentially life-threatening events such as pericardial tamponade, heart failure, syncope, arrhythmia, valvular stenosis or regurgitation, pulmonary hypertension, or peripheral blood vessel embolism may also occur[9]. In the absence of the characteristic signs and symptoms of cardiac echinococcosis, the diagnosis cannot be made on the basis of clinical manifestations alone. The definitive diagnosis of cardiac echinococcosis is based primarily on imaging techniques. The most commonly used imaging techniques include echocardiography, CT, and CMR[10]. Because of the difficulty in treating cardiac alveolar echinococcosis and the high mortality rate, it poses a significant threat to the health of the people in the affected areas. Therefore, its prognosis depends on early diagnosis and timely implementation of effective treatment.

Ultrasonography is an essential diagnostic imaging tool for the general investigation and clinical course of cardiac alveolar echinococcosis; however, ultrasonography is insufficient to assess the imaging features associated with cardiac alveolar echinococcosis in neighbouring lung tissue due to the influence of lung tissue. Both CT and CMR can suggest the location and imaging features of cardiac alveolar echinococcosis and reveal its relationship to neighbouring structures. Echocardiography is often the examination of choice for cardiac disease, providing diagnostic clues and a basis for the disease; depending on the location and condition of the lesion, further examinations can then be performed. CT and CMR can reveal some of the pathologic features of alveolar echinococcosis. These two imaging modalities are usually complementary[11]. MDCT examination can not only show the morphology, size, density, and calcification of the echinococcosis but also the relationship between the pericardial lesions and the surrounding structures (e.g., mediastinum, lungs, and heart, etc.), so MDCT has a unique value in the presentation of cardiac alveolar echinococcosis. On MDCT imaging, alveolar echinococcosis appears as inhomogeneous low-density masses, with calcification inside and at the edges of the lesion and liquefaction and necrosis in the centre of the lesion, constituting a map-like appearance; the edges of the lesion may be mildly intensified on enhancement scans, while the centre does not show significant enhancement, and small vesicles are the most characteristic manifestation of alveolar echinococcosis[12].

Cardiac alveolar echinococcosis usually presents as oval or spherical lesions with low signal on T1WI and signal intensity greater than or equal to cerebrospinal fluid on T2WI. The low-signal peripheral ring on the T2WI represents an encapsulation, which is typical Imaging manifestations of alveolar echinococcosis[12]. However, this low-signal ring is uncommon in cases of cardiac echinococcosis[13, 14].The imaging findings range from simple cystic lesions to complete solid appearance, making it difficult to distinguish from cardiac tumours. On an enhancement scan, the lesion does not enhance, but mild enhancement is seen at the edge of the lesion[15]. CMR examination can show small vesicles when CT and ultrasonography are not characteristic. Small vesicles show a high signal on T2WI, and a CMR scan shows multivesicular morphology more clearly, so it has an important value in diagnosing this disease. However, the calcification is not as good as that shown by CT and ultrasonography.

Regarding the differential diagnosis, cardiac alveolar echinococcosis needs to be differentiated from benign cysts or tumors such as pericardial cysts, epidermoid cysts, cystic teratomas, and cardiac sarcomas15. Pericardial cysts and epidermoid cysts do not enhance on the enhancement scan, whereas alveolar echinococcosis may show mild enhancement of the lesion margins on the enhancement scan[16, 17]. In addition, pericardial cysts and epidermoid cysts are usually free of calcification and small vesicle formation. Cystic teratomas and cardiac sarcomas differed significantly from cardiac alveolar echinococcosis in signal on T1WI and T2WI and showed marked or heterogeneous enhancement after gadolinium processing[18-20]. Thus, in cases of suspected alveolar echinococcosis, the presence of small vesicles and calcifications and mild enhancement of the margins of the lesion are crucial in differentiating it from other cardiac masses.

Early surgical excision is essential due to the insidious progression and dangerous complications of cardiac alveolar echinococcosis. Surgical treatment is usually feasible in the absence of rupture or purulent infection. The goal of surgical treatment is to avoid death from anaphylactic reactions or heart failure. The effectiveness of surgical treatment depends on the lesion's number, location and size and complications. In conclusion, Cardiac alveolar echinococcosis is extremely rare in modern life. Multimodal imaging is of great value in diagnosing cardiac alveolar echinococcosis, especially in areas where the disease is endemic, and the possibility of this disease should be considered. Considering the lethal complications and the poor prognosis, an early and accurate diagnosis is very important. Surgery should be performed as early as possible before the onset of the complications. In addition, the early application of anti-hydrogen disease drugs is indispensable for treating Cardiac alveolar echinococcosis.

MDCT multidetector computed tomography

CMR cardiac magnetic resonance

CTA computed tomography angiography

CE cystic echinococcosis

AE alveolar echinococcosis

T1WI T1-weighted imaging

T2WI T2-weighted imaging

Acknowledgements

Not applicable.

Author contributions

Mengdie Zhu was the primary participant in the case study. Zhu Mengdie prepared the manuscript. Xukun Gao and Li Meng revised and approved the manuscript. Xiaoping Wang provides guidance as well as administrative and technical support. All authors contributed to the article and acknowledged the submitted version.

Funding

This work was supported by the National Key Clinical Specialty Construction Project（Office of Health Commission of Qinghai Province (2024) No. 90），Qinghai Province “Kunlun Talents High-end Innovation and Entrepreneurial Talents” Top Talent Cultivation Project (No. 9,2023), and Chinese Red Cross Foundation's “Yingrui Northwest Charity Walk”（XM_HR_ICON_2020_10）.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Ethical Approval and Consent to Participate

The Ethics Committee of the Affiliated Hospital of Qinghai University waived the requirement for ethical approval of this case report, and consent was also not required because of the retrospective nature of the study.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Journal Editor.

Competing interests

All the authors have no conflicts of interest to declare.

Author details

1Department of Radiology, Affiliated Hospital of Qinghai University, Tongren Road No.29, Xining, 810001, PR China.

A JD, Chai JP, Jia SL, A XR. Historical changes in surgical strategy and complication management for hepatic cystic echinococcosis. World J Gastrointest Surg. 2023;15(8):1591-9.
Šimeková K, Rosoľanka R, Szilágyová M, Antolová D, Nováková E, Novák M, et al. Alveolar Echinococcosis of the Liver with a Rare Infiltration of the Adrenal Gland. Helminthologia. 2021;58(1):100-5.
Çelik D, Ödemiş I, Korkmaz M, Köse S. A rare case of cardiac alveolar echinococcosis without any complications for eight years. Rev Esp Quimioter. 2022;35(1):91-4.
Zhang X, Wei X, Ran L, Tang H. A rare case of cardiac alveolar echinococcosis. Eur Heart J. 2020;41(28):2698.
Bresson-Hadni S, Spahr L, Chappuis F. Hepatic Alveolar Echinococcosis. Semin Liver Dis. 2021;41(3):393-408.
Wen H, Vuitton L, Tuxun T, Li J, Vuitton DA, Zhang W, et al. Echinococcosis: Advances in the 21st Century. Clin Microbiol Rev. 2019;32(2).
Zhang R, Shen C, Rao L. Cardiac echinococcosis secondary to hepatic echinococcosis: a rare case report. Cardiovasc Diagn Ther. 2022;12(1):147-52.
Vazhev ZG, Stoev HA. Cardiac Echinococcosis Involving Left Ventricular Myocardium in an 18-Year-Old Patient. Folia Med (Plovdiv). 2018;60(2):308-13.
Firouzi A, Neshati Pir Borj M, Alizadeh Ghavidel A. Cardiac hydatid cyst: A rare presentation of echinococcal infection. J Cardiovasc Thorac Res. 2019;11(1):75-7.
Li T, Ito A, Pengcuo R, Sako Y, Chen X, Qiu D, et al. Post-treatment follow-up study of abdominal cystic echinococcosis in tibetan communities of northwest Sichuan Province, China. PLoS Negl Trop Dis. 2011;5(10):e1364.
Guo H, Liu W, Wang J, Xing Y. Extrahepatic alveolar echinococcus on multi-slice computed tomography and magnetic resonance imaging. Sci Rep. 2021;11(1):9409.
Gao X, Tan H, Zhu M, Wang Y, Zhang Y, Cao Y, et al. Hepatic alveolar echinococcosis accompanied by lung and kidney metastases: a case description of imaging findings. Quant Imaging Med Surg. 2024;14(1):1208-14.
Petik B, Hazirolan T, Uysal G, Erturk SM. Cardiac Hydatid Cysts: Computed Tomography and Magnetic Resonance Imaging Findings of the 5 Cases. J Comput Assist Tomogr. 2015;39(5):816-9.
Xing Y, Bawudong D, Zhang WB, Liu WY, Pan CX, Wen H, et al. Multidetector CT and MR imaging cardiac hydatidosis: case report and review of the literature. Int J Cardiovasc Imaging. 2011;27 Suppl 1:97-102.
Yılmaz R, Akpınar YE, Bayramoglu Z, Ozyavuz HI, Unal OF, Dursun M. Magnetic resonance imaging characteristics of cardiac hydatid cyst. Clin Imaging. 2018;51:202-8.
Yared K, Baggish AL, Picard MH, Hoffmann U, Hung J. Multimodality imaging of pericardial diseases. JACC Cardiovasc Imaging. 2010;3(6):650-60.
Meschisi M, Piccione MC, Bella GD, Zito C. Multimodalities Imaging in Diagnosis of Pericardial Cyst. J Cardiovasc Echogr. 2015;25(2):60-2.
Tower-Rader A, Kwon D. Pericardial Masses, Cysts and Diverticula: A Comprehensive Review Using Multimodality Imaging. Prog Cardiovasc Dis. 2017;59(4):389-97.
Abbas A, Garfath-Cox KA, Brown IW, Shambrook JS, Peebles CR, Harden SP. Cardiac MR assessment of cardiac myxomas. Br J Radiol. 2015;88(1045):20140599.
Buckley O, Madan R, Kwong R, Rybicki FJ, Hunsaker A. Cardiac masses, part 1: imaging strategies and technical considerations. AJR Am J Roentgenol. 2011;197(5):W837-41.

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Multimodal imaging for the diagnosis of cardiac alveolar echinococcosis: a case report

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