Retrospective Cohort Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 28, 2021; 27(40): 6939-6950
Published online Oct 28, 2021. doi: 10.3748/wjg.v27.i40.6939
Long-term follow-up of liver alveolar echinococcosis using echinococcosis multilocularis ultrasound classification
Jasmin Schuhbaur, Melissa Schweizer, Jana Philipp, Julian Schmidberger, Patrycja Schlingeloff, Wolfgang Kratzer
Jasmin Schuhbaur, Melissa Schweizer, Jana Philipp, Julian Schmidberger, Patrycja Schlingeloff, Wolfgang Kratzer, Department of Internal Medicine I, University Hospital Ulm, Ulm 89081, Germany
Author contributions: Kratzer W and Schuhbaur J planned and designed the study; The data were evaluated by Kratzer W and Schuhbaur J; all authors were involved in the interpretation of the results; Kratzer W, Schuhbaur J, Schmidberger J, Schlingeloff P, Schweizer M and Philipp J prepared the first draft; the statistical analysis was performed by Schmidberger J and Schlingeloff P; all authors read, amended, and approved the final version of the manuscript.
Institutional review board statement: The study was approved by the local ethics committee and conducted in accordance with the Declaration of Helsinki (ref. No. 166/13). Because of its retrospective design and pseudonymised evaluation of imaging, no ethics approval was necessary. All data were analysed anonymously.
Informed consent statement: Because of retrospective and anonymous character of this study, the need for informed consent was waived by the institutional review board.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: The datasets used and analyzed during the current study are available from the corresponding author on reasonable request (wolfgang.kratzer@uniklinik-ulm.de).
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Wolfgang Kratzer, MD, Professor, Department of Internal Medicine I, University Hospital Ulm, Albert-Einstein-Allee 23, Ulm 89081, Germany. wolfgang.kratzer@uniklinik-ulm.de
Received: July 20, 2021
Peer-review started: July 20, 2021
First decision: August 19, 2021
Revised: September 1, 2021
Accepted: September 22, 2021
Article in press: September 22, 2021
Published online: October 28, 2021
Processing time: 98 Days and 21.7 Hours
Abstract
BACKGROUND

When Echinococcus multilocularis infects humans as a false intermediate host, alveolar echinococcosis (AE) usually manifests primarily intrahepatically and is initially asymptomatic. If the disease remains undiagnosed and untreated, progressive growth occurs, reminiscent of malignant tumours. The only curative therapy is complete resection, which is limited to localised stages, and palliative drug therapy is used otherwise. Consequently, early diagnosis and reliable detection of AE lesions are important. For this reason, abdominal ultrasonography, as the most common primary imaging for AE, relies on classification systems.

AIM

To investigate how hepatic AE lesion sonomorphology changes over time in the Echinococcosis Multilocularis Ulm Classification (EMUC)-ultrasound (US) classification.

METHODS

Based on data from Germany’s national echinococcosis database, we evaluated clinical and US imaging data for 59 patients according to the AE case definition in our preliminary retrospective longitudinal study. There had to be at least two liver sonographies ≥ 6 mo apart, ≥ 1 hepatic AE lesion, and complete documentation in all US examinations. The minimum interval between two separately evaluated US examinations was 4 wk. The AE reference lesion was the largest hepatic AE lesion at the time of the first US examination. To classify the sonomorphologic pattern, we used EMUC-US. In addition to classifying the findings of the original US examiner, all reference lesions at each examination time point were assigned EMUC-US patterns in a blinded fashion by two investigators experienced in US diagnosis. Statistical analysis was performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, United Stated). P values < 0.05 were considered statistically significant.

RESULTS

The preliminary study included 59 patients, 38 (64.5%) women and 21 (35.6%) men. The mean age at initial diagnosis was 59.9 ± 16.9 years. At the time of initial ultrasonography, a hailstorm pattern was present in 42.4% (25/59) of cases, a hemangioma-like pattern in 16.9% (10/59), a pseudocystic pattern in 15.3% (9/59), and a metastasis-like pattern in 25.4% (15/59). For the hailstorm pattern, the average lesion size was 67.4 ± 26.3 mm. The average lesion size was 113.7 ± 40.8 mm with the pseudocystic pattern and 83.5 ± 27.3 mm with the hemangioma-like pattern. An average lesion size of 21.7 ± 11.0 mm was determined for the metastasis-like pattern. Although the sonomorphologic pattern remained unchanged in 84.7% (50/59) of AE reference lesions, 15.3% (9/59) showed a change over time. A change in pattern was seen exclusively for AE lesions initially classified as hemangioma-like or pseudocystic. A total of 70% (7/10) of AE lesions initially classified as hemangioma-like showed a relevant change in pattern over time, and 85.7% (6/7) of these were secondarily classified as having a hailstorm pattern, with the remainder (1/7; 14.3%) classified as having a pseudocystic pattern. A total of 22.2% (2/9) of AE lesions initially classified as pseudocystic showed a relevant change in pattern over time and were classified as having a hailstorm pattern. For AE lesions initially classified as having a hailstorm or metastatic pattern, no pattern change was evident. All patients with pattern change were on continuous drug therapy with albendazole.

CONCLUSION

The sonomorphology of hepatic AE lesions may change over time. The hemangioma-like and pseudocystic patterns are affected.

Keywords: Alveolar echinococcosis; Echinococcus multilocularis; Ultrasonography; Sonomorphology; Pattern change

Core Tip: Alveolar echinococcosis is potentially fatal. In approximately 98% of cases, it manifests in the liver, similar to a primary malignant or metastatic tumour. The sonomorphological appearance of the disease is varied and easily confused with other differential diagnoses. Sonography is the most important tool in diagnostics, but how the known patterns change over time is unclear. The evidence that certain sonographic patterns in particular change over time shows a possible evolutionary approach to the disease and may, in the long term, make lifelong drug therapy unnecessary in non-operable patients when non-active stages can be clearly identified.