Ultraschall in Med
DOI: 10.1055/a-1023-2333
Letter to the Editor
© Georg Thieme Verlag KG Stuttgart · New York

Diagnosis of Hepatic Hydatid Cysts by Contrast-Enhanced Ultrasound

Vitorino Modesto dos Santos
1  Internal Medicine, Catholic University of Brasília, Brazil
Lister Arruda Modesto dos Santos
2  General Surgery, State-Workers-Hospital, São Paulo-SP, Brazil, São Paulo, Brazil
› Author Affiliations
Further Information

Publication History

Publication Date:
24 October 2019 (online)

Dear Editors,

We have read the recently published manuscript related to the study of Schwarze V. et al. focusing on the application of contrast-enhanced ultrasound (CEUS) to assess hepatic lesions [1]. Six pregnant patients were safely evaluated based on CEUS images, which accurately diagnosed benign and malignant abnormalities including metastasis, focal hyperplasia, vascular changes, and cystic echinococcosis. The authors concluded that CEUS can be considered a safe diagnostic tool during pregnancy. Interestingly, this European study detected one woman presenting with unsuspected cystic echinococcosis that was immediately treated [1].

This finding would be a high occurrence even in the endemic regions of this zoonosis. The role of human infection by Echinococcus and its current status as an emerging public health problem due to poor control of transmission by infected livestock must be highlighted. The practical value of the research is unquestionable and it will surely stimulate further studies about this condition categorized as a neglected disease by the World Health Organization.

Human beings may be accidentally infected either by ingesting contaminated food or water, or by direct animal contact [2] [3] [4]. Therefore, unsuspected infections and cysts evolving symptomless often present diagnostic challenges in non-endemic areas. Differential diagnoses include: bile cyst, cystadenoma, cystadenocarcinoma, cholangiocarcinoma, cystic metastases, hamartoma, hemangioma, abscesses, pseudocysts, hematoma, and aneurysms [2].

Jain et al. reviewed the data of 38 Indian patients, between 20 and 55 years of age and including 76 % males, with a diagnosis of hydatidosis based on ultrasound and computed tomography [3]. The cysts were found in the liver (71.1 %), kidney (10.5 %), and peritoneum (8 %), followed by the pancreas, spleen, common bile duct, and adnexa (2.6 % each). Except for the liver, the locations of the hydatid cysts were not in accordance with the literature, a phenomenon that causes late diagnoses and risk of rupture during routine diagnostic puncture of the cyst [3].

Moradi et al. evaluated 682 surgical patients in Iran. 53.5 % were female, 24.9 % had hydatid cysts, and 27.5 % of 404 hepatic interventions were done to treat hydatid cysts [4]. The involvement of the liver was higher than that of the lungs, with greater significance in women, while the highest prevalence of hepatic echinococcosis occurred in the 26–35-year-old group. The high proportion of hepatic cysts may be due to the role of the filtering of the ingested ova from the blood, and the prevalence in women can be related to their increased contact with sources of infection. Patients over 76 years of age had the lowest number of interventions for hydatid cysts although this kind of cyst usually develops with an increase of one to five centimeters per year [4].

We would like to add information about a giant hydatid cyst of the liver found in an 87-year-old Brazilian woman in 2008, following a visit to a sheep farm in an endemic area of hydatidosis [2]. She had Parkinson’s disease and was admitted because of food bronchoaspiration. Incidentally, the ultrasonography study revealed a huge abdominal mass with solid matrix, cystic areas and ring-like calcifications. The major initial concern was a cystic malignant tumor, which could not be ruled out based on ultrasound images without contrast. Therefore, additional evaluation with contrast-enhanced computed tomography of the abdomen revealed a giant loculated cystic-solid mass surrounded by daughter cysts and calcifications. Further confirmatory findings of hepatic echinococcosis were positive IgG antibodies by indirect immune fluorescence, and the typical histopathological images of protoscolices of E. granulosus fixed in the germinative membrane. After the biopsy evaluation, the elderly woman underwent continuous cycles of albendazole [2].

The most affected organ is the liver, with predominance among women in many countries. The purpose of the retrospective European study was to assess the diagnostic usefulness and safety of CEUS for the routine evaluation of hepatic lesions in pregnant patients. The favorable conclusion of the study could be further complemented by the utilization of CEUS for abdominal screening in patients living in high endemic regions of echinococcosis. Moreover, public health education all over the world should emphasize the main mechanisms of transmission, including the role of infected dogs and contaminated food and water.