Hydatid Cyst of the Liver complicated with a Fistula into the inferior Vena Cava

Abstract

Hydatid disease remains a significant public health concern in endemic countries such as Tunisia. Among its rare but serious complications is the rupture of a liver hydatid cyst into the inferior vena cava (IVC), leading to a wide range of clinical presentations and outcomes. This article reports 2 illustrative cases. The first involves a 45-year-old patient with recurrent right hypochondria pain, where imaging revealed a 6 cm liver cyst near the IVC. Surgical management included cyst resection and kysto-caval fistula repair, followed by recovery from a postoperative infection. The second case describes a 60-year-old woman with comorbidities, presenting with dyspnea and pain, where imaging showed multiple thromboses and a hepatic cyst; she was successfully managed conservatively with anticoagulants and Albendazole. These cases underscore the importance of timely diagnosis and tailored treatment for this rare but potentially life-threatening condition.

Introduction

Hydatid disease remains a major public health concern in highly endemic regions such as Tunisia [1], where livestock breeding and close human-animal contact facilitate the parasite’s transmission cycle. Caused by the larval stage of Echinococcus granulosus, the disease most commonly affects the liver, where cysts may grow silently over years before causing complications. Among these, rupture into vascular structures such as the inferior vena cava (IVC) is exceptionally rare but potentially life-threatening [2]. This complication can lead to a wide spectrum of clinical manifestations, ranging from asymptomatic cases to catastrophic events like pulmonary embolism or systemic hydatidosis. Early recognition and tailored management are crucial for favorable outcomes. This article presents 2 distinct clinical cases illustrating the diverse presentations, therapeutic challenges, and outcomes associated with hepatic hydatid cyst rupture into the IVC. This work is reported in line with the SCARE guideline [3].

Case 1

We report the case of a 45-year-old male patient with no chronic illnesses such as diabetes, hypertension, or cardiovascular disease. His surgical history included a Lagrot procedure performed 20 years earlier for a hydatid cyst located in segment VII of the liver. There was no significant family history of hydatid disease or other hereditary conditions. The patient lived in a rural region of Tunisia with continued exposure to livestock and domestic dogs, known risk factors for Echinococcus granulosis infection.

The patient presented with a 1-year history of persistent right hypochondrial pain and a sensation of heaviness, without fever, jaundice, weight loss, or respiratory symptoms. Physical examination was unremarkable, revealing no palpable mass, hepatomegaly, or signs of chronic liver disease. Vital signs were stable, and there were no signs of cardiac or pulmonary compromise.

Routine laboratory tests were within normal limits:

• White Blood Cells: 7,800/mm³ (Normal: 4000-10,000/mm³)

• Hemoglobin: 14.2 g/dL (Normal: 13-17 g/dL)

• Platelets: 265,000/mm³ (Normal: 150,000-400,000/mm³)

• C-reactive protein: 3 mg/L (Normal: <5 mg/L)

• AST: 30 U/L (Normal: <40 U/L), ALT: 26 U/L (Normal: <41 U/L)

• Total bilirubin: 0.7 mg/dL (Normal: 0.3-1.2 mg/dL)

• Renal function and electrolytes were within normal ranges.

• Echinococcus serology was not repeated at this stage.

A thoraco-abdominal CT scan confirmed the recurrence of a hydatid cyst in liver segment VII, measuring 6 cm in its largest dimension. The cyst was closely related to the inferior vena cava (IVC), and imaging suggested the possible presence of a kysto-caval fistula (Fig. 1). Importantly, there were no signs of hydatid material migrating into the vena cava, the right heart chambers, or the pulmonary arteries, ruling out pulmonary embolization or secondary hydatidosis.

Fig. 1.

CT scan showing the hydatid Cyst (red arrow) and the fistula into the Vena Cava (yellow arrow).

Given the close proximity to the IVC, a conservative surgical approach was selected. After mobilization of the liver, the hepatic pedicle and both the suprahepatic and infrahepatic portions of the IVC were controlled and kept on standby for clamping in case of bleeding (Fig. 2A). A protruding dome resection was performed (Fig. 2B). Upon aspirating the cyst contents, a small kysto-caval fistula was identified with active bleeding (Fig. 2C). Hemostasis was achieved by careful suturing of the fistula.

Fig. 2.

(A) Intraoperative images: Dissection and isolation of the inferior Vena Cava and the Hepatic Pedicle. (B) Intraoperative images: resection of the corticalized pericyst (externalized extrahepatic). (C) Intraoperative images: the Cysto-caval Fistula (white arrow).

Postoperative recovery was complicated by the development of an infectious pneumopathy, which was effectively treated with broad-spectrum antibiotics, leading to clinical improvement. The patient was discharged in stable condition on postoperative day 15.

At the 1-year follow-up, the patient remained asymptomatic, with no evidence of hydatid cyst recurrence or vascular complications on follow-up imaging.

Case 2

We report the case of a 60-year-old female patient with a medical history notable for hypertension, type 2 diabetes mellitus, and dyslipidemia, all managed with long-term pharmacological therapy. She had no prior surgical history and no known allergies. There was no family history of hydatid disease or thromboembolic disorders, and no significant occupational exposure, although she resided in an endemic rural region where hydatid disease is prevalent due to close contact with livestock and stray dogs.

The patient presented to the emergency department for progressively worsening dyspnea over several months, which had acutely intensified 1 week before admission. She also reported intermittent, poorly localized right hypochondrial pain described as a heavy sensation, present for 2 years but never previously investigated. She denied fever, cough, hemoptysis, chest pain, or digestive symptoms.

On physical examination, the patient was tachypneic with a respiratory rate of 26 breaths per minute, and her oxygen saturation was 95% on room air. Lung auscultation was clear, and no cardiac murmurs were noted. Her cardiovascular exam was otherwise unremarkable. Electrocardiography revealed sinus tachycardia with signs of right ventricular strain. Arterial blood gas analysis showed mild hypoxemia with a shunt effect, consistent with impaired pulmonary perfusion. Chest X-ray was normal, showing no evidence of pneumonia or other pulmonary pathology.

Laboratory tests were as follows:

• White blood cell count: 8500/mm³ (Normal: 4000–10,000/mm³)

• Hemoglobin: 12.8 g/dL (Normal: 12-16 g/dL)

• Platelet count: 280,000/mm³ (Normal: 150,000–400,000/mm³)

• C-reactive protein: 4 mg/L (Normal: <5 mg/L)

• Fasting blood glucose: 140 mg/dL (Normal: 70-110 mg/dL) reflecting her known diabetes

• Creatinine: 0.9 mg/dL (Normal: 0.6-1.1 mg/dL)

• Liver enzymes and coagulation profile were within normal ranges.

• Echinococcus serology was not performed due to the urgent clinical context.

Given the clinical suspicion of pulmonary embolism, a thoraco-abdominal angio-CT scan was performed. It demonstrated multiple hypodense filling defects in the inferior vena cava and pulmonary artery branches, consistent with multiple thrombi (Fig. 3). Additionally, the abdominal cuts revealed a hydatid cyst in the right lobe of the liver, in close contact with the retrohepatic segment of the inferior vena cava (Fig. 4), suggesting a possible cyst rupture into the venous system, resulting in hydatid embolism.

Fig. 3.

AngioCT scan revealing multiple embolisms (yellow arrows).

Fig. 4.

Hepatic hydatid cyst in close proximity to the retrohepatic vena cava (yellow arrow).

Considering the patient’s comorbidities and her refusal of surgical intervention, a conservative management approach was adopted. She was started on anticoagulation therapy with low molecular weight heparin, transitioned to oral anticoagulants, and received Albendazole at a dose of 400 mg twice daily to address the hydatid infection. Her respiratory symptoms improved gradually, and no additional embolic events were observed during hospitalization.

The patient was discharged after stabilization with plans for close outpatient monitoring. At 6 months of follow-up, she remained clinically stable without recurrence of dyspnea or thromboembolic complications. Despite counseling on the benefits of surgical management, she continued to decline operative intervention and maintained her treatment with Albendazole and anticoagulation under regular clinical and radiological surveillance.

Discussion

The spontaneous rupture of a liver hydatid cyst into the inferior vena cava (IVC) is an exceedingly rare occurrence, with only a dozen reported cases in the medical literature [2]. The primary symptomatology associated with this condition is pulmonary embolism, a phenomenon seldom described and more often discovered in postmortem [4]. Perioperative and postmortem data indicate that the embolism is purely mechanical, resulting from the obstruction caused by the cyst and its “daughter” vesicles. There are no signs of clots or associated thrombosis. In theory, one might expect hemorrhagic shock to be the main complication resulting from the spontaneous rupture of a hydatid cyst into the IVC. However, this has never been documented in the literature, and it may be explained by the intracystic pressure being higher than that within the vena cava.

A Liver hydatid cyst ruptured into the vena cava can also be incidentally discovered through indirect radiological signs, as was the case with patient 1.

From a radiological standpoint, the CT scan remains the most effective diagnostic tool for elucidating the vascular relationships of the hydatid cyst, particularly its relationship with the IVC [5]. In this examination, the rupture of a KHF into the IVC is suspected when a hydatid cyst is observed in the posterior segments of the liver (VII, VIII, and I) in close proximity to the IVC. The IVC may appear compressed or flattened by the cyst, sometimes containing thrombotic material or hydatid debris [6]. MRI, Doppler ultrasound, and cavography can further confirm the presence of cystic lesions within the retrohepatic vena cava and the pulmonary artery. In the case of patient 1, the CT scan revealed a KHF in the posterior segments of the right liver, compressing the IVC with partial thrombosis. Patient 2′s scan showed hydatid pulmonary embolism and the presence of vesicles in the right heart.

The treatment of a ruptured liver hydatid cyst in the IVC is surgical. Two major perioperative complications must be considered: massive intraoperative pulmonary embolism and rapid hemorrhage. Hence, preoperative vascular control is imperative before any surgical procedure [6]. The hydatid cyst must be handled with extreme care, and any cyst-venous communication must be sought and closed. The absence of blood within the cystic cavity does not rule out KHF rupture into the IVC [7]. This can be explained by the fact that intracystic pressure exceeds intravenous pressure. Our case supports this theory, as there were no signs of intracystic bleeding upon surgical exploration. After evacuating the cyst's contents, the fistula became evident. The management of hydatid pulmonary embolism can be performed during the same surgical procedure or at a later stage. The removal of daughter vesicles from the pulmonary artery trunk and its proximal branches is typically conducted under extracorporeal circulation (ECC) via arteriotomy [8]. Medical treatment is indicated in cases of chronic embolism, extensive dissemination of daughter vesicles throughout the pulmonary arterial tree, or contraindications to surgery [5]. In cases where surgery is refused, endovascular treatment may be considered, involving the placement of an endovascular prosthesis in the retrohepatic vena cava to seal the cysto-caval fistula [9].

Conclusion

The rupture of a liver hydatid cyst into the inferior vena cava can manifest in various ways, from an entirely asymptomatic course to a life-threatening hydatid pulmonary embolism. Clinicians must maintain a high index of suspicion in patients at risk and be prepared to intervene promptly when necessary. Further research is needed to establish guidelines for managing asymptomatic cases and to refine diagnostic and therapeutic strategies to improve outcomes for patients presenting with this rare but challenging condition.

Patient consent

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