Table 3.

PNM classification of Echinococcus multilocularis[146]

P	Hepatic localization of the metacestode
Px	Primary lesion unable to be assessed
P0	No detectable hepatic lesion
P1	Peripheral lesion without biliary or proximal vascular involvement
P2	Central lesions with biliary or proximal vascular involvement of one lobe
P3	Central lesions with biliary or proximal vascular involvement of both lobes or two hepatic veins or both
P4	Any lesion with extension along the portal vein, inferior vena cava or hepatic arteries
N	Extra-hepatic involvement of neighbouring organs
Nx	Not evaluable
N0	No regional involvement
N1	Involvement of neighboring organs or tissues
M	Absence or presence of distant metastasis
Mx	Not completely assessed
M0	No metastasis on chest radiograph and computer tomography brain scan
M1	Metastasis present