Hydatid cyst of the liver rupturing into the portal vein: A rare complication

Abstract

Hydatid cyst of the liver is a zoonosis caused by parasite Echinococcus granulosus, which remains highly prevalent in Morocco. Current medical imaging modalities, particularly ultrasonography (US) and computed tomography (CT), facilitate rapid and accurate diagnosis, enable effective treatment possibilities and allow for easy follow-up. Complications are typically dominated by infection and rupture, especially in the bile ducts, peritoneal cavity, and chest. Dissemination and development within vascular structures, especially the portal vein, are much less common. This underscores the significance of our case, which illustrates this rare complication of hydatid cyst of the liver.

Introduction

As parasitosis is still endemic in Morocco, hepatic hydatidosis is a generally benign disease with varying clinical appearance.

However, this condition can become life-threatening through its various complications, particularly vascular ones.

In this radiological observation, we present a clinical case of a hydatid disease complicated by portal vein involvement and cavernous transformation.

Case report

The patient, a 55 years old man who had been undergoing treatment for hepatic hydatidosis with albdendazole for 3 months, presented to the emergency department with symptoms of angiocholitis: right hypochondrium pain, jaundice, and fever. Biological tests indicated cholestasis and liver cytolysis with positive infection markers (hyperleukocytosis at 13,000/mm³ and CRP at 200 mg/L).

Abdominal ultrasonography revealed multiple anechoic formations, some of which communicated with each other, with one showing calcifications. The imaging also demonstrated a dilated portal vein, common bile duct, and intrahepatic bile ducts. Doppler mode detected a numerous tortuous vessels occupying the portal vein bed, without color flow in the portal vein.

A thoracic-abdomino-pelvic CT scan with contrast injection confirmed the presence of multiple intercommunicating cystic lesions, the largest of which was aligned with the proximal branches of the portal division. These lesions were hypodense, heterogeneous, and fluid-dense. Additionally, peribiliary serpigineous vein structures indicative of cavernous transformation was observed. The largest formation also showed fistulization into the intrahepatic bile ducts which were dilated (Fig. 1).

Fig. 1.

Abdominal ct scan with contrast showing the communication () between hydatid cyst () and portal vein () which is thrombosed and complicated by a cavernous transformation ().

The diagnosis was complicated hepatic hydatidosis with portal venous thrombosis, cavernous transformation, and cysto-biliary fistulae.

A biliary MRI further demonstrated the development of the hydatic cyst within the intrahepatic bile ducts and the portal system, complicated by a portal cavernoma (Fig. 2).

Fig. 2.

MRI demonstrating multiple hydatid cysts which are heterogeneous, hypointense on T1, and hyperintense on T2 with enhanced walls after contrast, their communication with the portal vein and portal cavernoma transformation.

The therapeutic approach involved initiating anticoagulant therapy and continuing anthelmintic treatment with rigorous radiological follow-up (Fig. 3). The patient's condition improved favorably after 24 months.

Fig. 3.

Control biliary MRI (6 months later): stability of previous imaging statements.

Discussion

Classically considered a benign zoonosis caused by the intrahepatic development of Echinococcus granulosus [1], hepatic hydatidosis can nonetheless be serious and fatal, particularly in cases of vascular complications. Although rare, these complications are the most dangerous, occurring as a result of compression or rupture [2]. Vascular compression is the most common mechanism. During its development, and in the absence of treatment, the hydatic cyst can compress surrounding structures including vessels [3]. The direct opening of the hydatic cyst into vessels is exceptional, either through adjacent vascular invasion or by rupture [4] as seen in our patient's case.

This is due to the abundance of elastic fibers in the vascular wall, which give it compliance properties and make it difficult to rupture, unlike the bile ducts whose rigidity predisposes them to easily rupture [4]. The cysts responsible for these complications are most often of peri-sus-hepatic-cave location or retro-hepatic development (segment I). Usually, rupture occurs in the inferior vena cava (IVC), in the hepatic veins and rarely in the right renal vein [5]. Opening into the portal vein has only been reported in a few cases in the literature. Clinically, vascular compression is usually well tolerated [3]. However vascular complications manifest in various forms of varying severity: portal hypertension, Budd-Chiari syndrome, cholestasis syndrome due to portal biliopathy (as in our case), or even by anaphylactic shock or pulmonary embolism if rupture occurs in the IVC [6].

Diagnosis relies heavily on imaging; Doppler ultrasonography being the preferred imaging modality [7]. It allows for the diagnosis of hepatic hydatid cyst, providing detailed information regarding their location, contents, number, as well as their vascular and biliary relationships. Doppler ultrasonography can also accurately identify portal thrombosis by detecting hypoechoic material and the absence of flow, and it can even visualize small anechoic formations within the obstructing material, indicative of daughter vesicles. Additionally, it reveals collateral venous circulation characterized by multiple serpentine venous structures of varying sizes and monophasic flow, consistent with portal cavernoma [2].

It is essential to complement with a CT scan, which accurately evaluates the relationship between the hydatic cyst and adjacent vessels and objectively confirms communication between the portal vein and the hydatic cyst, as observed in our case. Additionally, performing a biliary MRI may offer valuable insights. This modality is particularly useful for diagnosing multiple and atypical forms, allowing for a more personalized treatment planning. However, while imaging can rule out vascular compression, it may not definitively exclude communication between the hydatic cyst and adjacent vessels if not clearly evident, as is our patient's case. Evaluating the thickness of the liver parenchyma between the cyst and the vascular lumen on CT can serve as a useful guide [2].

Treatment typically involved a combination of medical and surgical approaches aimed at with removing the obstruction. If surgery is chosen, it should be meticulously planned and conducted at specialized liver and vascular surgery centers due to the non-negligible intraoperative mortality risk. Upon evacuation of the cystic contents during surgery, abrupt pressure drops can occur, leaving the breach uncovered and potentially leading to intra-cystic bleeding [8]. Some surgical teams recommend intraoperative use of albendazole to prevent hydatid dissemination and recurrence [9].

Considering the inherent risks associated with surgery, medical treatment with regular radiological follow-up may sometimes be deemed the optimal therapeutic option, as discussed in our patient's case. Therefore, accurate diagnosis of various liver hydatic cyst complications, especially vascular ones, on preoperative imaging holds significant clinical relevance.

Conclusion

Although rarely described in the literature, vascular complications of liver hydatic cyst should not be overlooked because of their significant morbidity. Imaging plays a central role in their diagnosis, providing precise vascular and lesion mapping, guiding treatment choices, and helping lower intraoperative risks.

Author agreement statement

We the undersigned declare that this manuscript is original, has not been published before and is not currently being considered for publication elsewhere. We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us. We understand that the Corresponding Author is the sole contact for the Editorial process. He/she is responsible for communicating with the other authors about progress, submissions of revisions, and final approval of proofs signed by all authors as follows:

I.Guemmi

H.Mahjouba

C.Ziani

K.Oukrid

S.Nasri

I. Kamaoui

I. Skiker

Patient consent

The patient has been informed and consents to the publication of this article.