Alveolar echinococcosis-spreading disease challenging clinicians: a case report and literature review

Abstract

Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging.

Keywords: Alveolar echinococcosis; Autochthonous infection; Echinococcus multilocularis; Hemihepatectomy; Liver resection.

Figure 1

Radiological findings prior and after curative resection. A, B: Computed tomography of the abdomen displaying an extended tumour manifestation prior to resection; C: Computed tomography of the abdomen following extended left hemihepatectomy; D-F: Computed tomography of the abdomen prior to resection. Arrows: possible extensive adhesions to adjacent pancreatic head and corpus. AE: Alveolar echinococcus tumour; P: Pancreas.

Figure 2

Referral evaluations for diagnosis of alveolar echinococcosis. A: The hematoxylin and eosin stain of paraffin sections displays the laminated layer as a narrow band (long arrows). The germinal layer is marked by short arrows; B: Periodic acid-Schiff (PAS) stain shows a strongly PAS-positive basophilic laminated layer displaying a bizarre narrow structural pattern. The long arrows indicate the typical severe inflammatory process associated with the characteristic tubular growth pattern of the parasite.

Figure 3

Histological findings after curative resection. Hematoxylin and eosin stain of paraffin sections displaying two daughter cysts containing no vital protoscoleces embedded in a larger lesion. Black arrows indicate avital protoscoleces.