Pathology of Echinococcosis: A Morphologic and Immunohistochemical Study on 138 Specimens With Focus on the Differential Diagnosis Between Cystic and Alveolar Echinococcosis

Infection of humans by the larval stage of the tapeworms Echinococcus granulosus sensu lato or Echinococcus multilocularis causes the life-threatening zoonoses cystic echinococcosis (CE) and alveolar echinococcosis (AE). Although cystic liver lesions are a hallmark of both diseases, course, prognosis, and patients’ management decisively differ between the two. The wide and overlapping spectrum of morphologies and the limited availability of ancillary tools are challenges for pathologists to reliably diagnose and subtype echinococcosis. Here, we systematically and quantitatively recorded the pathologic spectrum in a clinically and molecularly defined echinococcosis cohort (138 specimens from 112 patients). Immunohistochemistry using a novel monoclonal antibody (mAbEmG3) was implemented, including its combined application with the mAbEm2G11. Six morphologic criteria sufficiently discriminated between CE and AE: size of smallest (CE/AE:>2/≤2 mm) and largest cyst (CE/AE:>25/≤25 mm), thickness of laminated layer (CE/AE:>0.15/≤0.15 mm) and pericystic fibrosis (CE/AE:>0.6/≤0.6 mm), striation of laminated layer (CE/AE: moderate-strong/weak), and number of cysts (CE/AE: ≤9/>9). Combined immunohistochemistry with mAbEm2G11 (E. multilocularis specific) and mAbEmG3 (reactive in AE and CE) was equally specific as and occasionally more sensitive than polymerase chain reaction. On the basis of these findings, we developed a diagnostic algorithm for the differential diagn...
Source: The American Journal of Surgical Pathology - Category: Pathology Tags: Original Articles Source Type: research