Minireviews
Copyright ©2014 Baishideng Publishing Group Co.
World J Surg Proced. Mar 28, 2014; 4(1): 13-20
Published online Mar 28, 2014. doi: 10.5412/wjsp.v4.i1.13
Table 1 PNM classification of alveolar echinococcosis
PPrimary lesion localized to the liver
PXPrimary lesion cannot be assessed
P0No detectable hepatic lesion
P1Peripheral hepatic lesion with no proximal hepatic vascular or biliary involvement
P2Central hepatic lesion with proximal involvement of vessels or biliary ducts in one lobe1
P3Central hepatic lesion with involvement of hilar vessels or biliary ducts in both lobes or with involvement of two hepatic veins
P4Hepatic lesion with extension along the vessels2 and biliary tree
NExtrahepatic involvement of neighboring organs or tissues [diaphragm, lung, pleura, pericardium, heart, gastric or duodenal wall, adrenal gland, peritoneum, retroperitoneum, parietal wall (muscles, skin, bone), pancreas, regional lymph nodes, hepatic ligaments, kidney]
NXCannot be evaluated
N0No regional involvement
N1Regional involvement of contiguous organs or tissues
MAbsence or presence of distant metastasis (in lung, distant lymph nodes, spleen, central nervous system, orbits, bone, skin, muscle, kidney, distant peritoneum, and retroperitoneum)
MXNot completely evaluated
M0No metastasis3
M1Metastasis
Table 2 Morphological characteristics of hepatic alveolar echinococcosis lesions
ModalityHepatic AE lesions
USMass with irregular margins, scattered foci of calcification, central necrosis, and vascular and biliary involvement
CT
UnenhancedMass with irregular margins, hyperattenuating foci of calcification, and hypoattenuating regions of necrosis and parasitic tissue
Contrast- enhancedMass with no substantial enhancement and peripheral fibroinflammatory components with slight but long-lasting enhancement
CT perfusionLower BF, BV, ALP and PVP values in AE lesions compared with normal liver parenchyma
MRI
T1-weightedHeterogeneous mass with irregular margins and a necrotic center that exhibits low to intermediate signal intensity
T2-weightedHeterogeneous mass with irregular margins, a necrotic center that exhibits high signal intensity, and low-signal-intensity fibrotic and collagenous components
Contrast-enhancedMass with no substantial enhancement and peripheral fibroinflammatory components with slight but long-lasting enhancement
Diffusion-weightedMass with hypointense signal and high ADC on images obtained with high b values