Proposal of an ultrasonographic classification for hepatic alveolar echinococcosis: Echinococcosis multilocularis Ulm classification-ultrasound

Ultrasonographic findings of small lesion of hepatic alveolar echinococcosis

OBJECTIVE

To investigate the features of small lesions of hepatic alveolar echinococcsis paragonimiasis (AE) on conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) imaging.

METHODS

This retrospective study was approved by the Institutional Review Board, and the requirement for informed consent was waived. US and CEUS features of seventeen lesions histopathologically proven hepatic AE were retrospectively reviewed. Nine patients with seventeen hepatic AE lesions who were admitted to our hospital between January 2008 and June 2015 were enrolled. All hepatic AE lesions were small (≤3cm). The US and CEUS examinations were performed with a Philips IU22 scanner with a 1-5-MHz convex transducer. After US was completed, the CEUS study was performed. Pulse-inversion harmonic imaging was used for CEUS. A bolus injection of 2.4mL of a sulfur-hexafluoride-filled microbubble contrast agent (SonoVue) was administered. The features of the lesions by US and CEUS were retrospectively reviewed.

RESULTS

In total, all lesions were detected by US and CEUS. The mean size of the lesions was 1.8±0.7cm (range: 1.0-3.0cm). Five patients (55.6%, 5/9) had a lesion in the right hepatic lobe; two (22.2%, 2/9) had two lesions in the left hepatic lobe; and two patients (22.2%, 2/9) had four lesions in the right lobe. Seven lesions (41.2%, 7/17) were hypoechoic nodules and ten (58.8%, 10/17) were hyperechoic nodules. Nine lesions (52.3%, 9/17) were of mixed echogenicity type. Ten lesions (58.8%, 10/17) had a regular shape. Nine lesions (52.3%, 9/27) had a sharp margin and six (35.3%, 6/17) had indistinct margins. Four lesions (57.1%, 4/7) with hypoechoic nodule had small dotted calcifications, none was found in hyperechoic nodule. Seven nodules (41.2%, 7/17) showed short striated blood-flow signals surrounding the margin, on color Doppler flow imaging. By CEUS, All the lesions were hypoechoic with mixed content (). 12 lesions (70.1%, 12/17) were rim enhanced with irregular piece-like nonenhanced internal areas and showed nonhomogeneous hypo-enhancement during the arterial phase, with mixed echogenicity. The main pathological findings included: (1) (1) coagulative or liquefactive necrosis within the lesion with sporadic distribution of wizened alveolar hydatid cysts; and (2) hyperplasia of granulomatous and fibrous tissue around the lesion.

CONCLUSION

Hyperechogenicity, mixed echogenicity type, dotted calcification with hypoechogenicity, sharp margin, rim enhancement and piece-like nonenhanced areas could be seen as the main ultrasonographic features of small lesion of hepatic alveolar echinococcosis.

Vertebral alveolar echinococcosis-a case report, systematic analysis, and review of the literature

Alveolar echinococcosis caused by Echinococcus multilocularis is an infrequent zoonosis with a high degree of disability, morbidity, and mortality, especially in disease clusters of the northern hemisphere. The diagnosis is complicated by extended incubation time, diverse clinical manifestations, and mimicking of differential diagnoses. The primary organ affected is the liver, but extrahepatic disease is possible, with vertebral involvement in only a few dozen cases described worldwide. Although vertebral alveolar echinococcosis seems to be rare, it might be under diagnosed, and it might be seen more often as the number of people with immunocompromised conditions increases. Recognition of this syndrome is crucial, because advances in medical and surgical management strategies since the introduction of benzimidazole in 1976 have controlled and relieved symptoms in most cases. In this Grand Round, we present the case of a 75-year-old woman who was referred for biopsy of a lumbar lesion 3 months after she was diagnosed with chronic myeloid leukaemia. The diagnosis of hepatic alveolar echinococcosis with metastasis to the lumbar spine and paravertebral region as well as the brain was confirmed by biopsy, PCR, and serology. The patient was given albendazole and referred for palliative surgery with the aim of pain control. Clinical features of the case are presented and discussed in the context of the literature. This case and review illustrate the complexity of extrahepatic alveolar echinococcosis manifestations and the necessity of an interdisciplinary approach.

To see or not to see: non-invasive imaging for improved readout of drug treatment trials in the murine model of secondary alveolar echinococcosis

Alveolar echinococcosis (AE) is an emerging zoonotic disease caused by the cestode Echinococcus multilocularis. The secondary infection model of AE is based on intraperitoneal injection of disease-causing metacestodes into the peritoneal cavity of mice, which allows investigations on novel drugs or immunotherapeutical treatment options in vivo. So far, such in vivo studies assessed exclusively the parasite weight at the endpoint of a given treatment period. We here developed an ultrasound (US)-based scoring system that allows to follow-up parasite development in the living animal, and provides insights into parasite growth during the treatment phase. By this method a statistically significant difference between untreated and medicated mice with E. multilocularis infection was observed at 2 months post-infection, and the growth curve of the parasite load was described by a linear mixed model. High correlation and similar levels of variation were observed for the standard method based on parasite weight measurement, the novel US-based scoring system, as well volume segmentation by post-mortem magnetic resonance imaging. Thus, US-based scoring in the live animal has the potential to assist the 3R concept by contributing to the refinement and reduction of animal use in experimental echinococcosis.

The Echinococcoses: Diagnosis, Clinical Management and Burden of Disease

The echinococcoses are chronic, parasitic diseases that are acquired after ingestion of infective taeniid tapeworm eggs from certain species of the genus Echinococcus. Cystic echinococcosis (CE) occurs worldwide, whereas, alveolar echinococcosis (AE) is restricted to the northern hemisphere, and neotropical echinococcosis (NE) has only been identified in Central and South America. Clinical manifestations and disease courses vary profoundly for the different species of Echinococcus. CE presents as small to large cysts, and has commonly been referred to as 'hydatid disease', or 'hydatidosis'. A structured stage-specific approach to CE management, based on the World Health Organization (WHO) ultrasound classification of liver cysts, is now recommended. Management options include percutaneous sterilization techniques, surgery, drug treatment, a 'watch-and-wait' approach or combinations thereof. In contrast, clinical manifestations associated with AE resemble those of a 'malignant', silently-progressing liver disease, with local tissue infiltration and metastases. Structured care is important for AE management and includes WHO staging, drug therapy and long-term follow-up for at least a decade. NE presents as polycystic or unicystic disease. Clinical characteristics resemble those of AE, and management needs to be structured accordingly. However, to date, only a few hundreds of cases have been reported in the literature. The echinococcoses are often expensive and complicated to treat, and prospective clinical studies are needed to better inform case management decisions.

Comprehensive diagnosis and treatment of alveolar echinococcosis: A single-center, long-term observational study of 312 patients in Germany

Alveolar echinococcosis (AE) is the most Iethal human helminthic infection. The malignancy-like disease is rare, but morbidity and treatment costs are high. Objective of the study was to identify factors at baseline and during specific AE therapy influencing the long-term outcome of the disease.

All patients with AE seen at the specialized treatment unit in Ulm between January 1992 and December 2011 were included in the analysis.

The data of 312 patients were analyzed; 108 were diagnosed before 2000 (series A), 204 since 2000 (series B); 290 received specific AE treatment. Patients of series B were more often symptom-free at diagnosis (44.1% vs. 21.3%), had lower disease stages (50.0% vs. 34.2%) and more complete resections (57.7% vs. 20.0%), but higher rates of side effects and drug toxicity (54.1% vs. 40.8%). In series B, more patients remained relapse- or progression-free after 5 years (90.5% vs. 82.8%); after 10 years, the ratio of relapses converged (70.3% vs. 66.9%, p=0.0507). Relapses or progression occurred more often after incomplete surgery or long treatment pauses. The 5-year and 10-year survival rates were 96.9% and 90.6%, respectively, and 17% of the patients were cured.

We observed a shift towards early diagnosis, earlier initiation of specific therapy and more complete resections after 2000. Although diagnosis and treatment of AE pose a challenge, with an individual interdisciplinary management 88.8% of the patients have a favorable outcome.