WHO-IWGE PNM classification for alveolar echinococcosis (AE).
P | Hepatic localization of parasitic structures. |
PX | No evaluation possible |
P0 | No evidence of hepatic involvement |
P1 | Peripheral focus without involvement of proximal vessels or bile ducts |
P2 | Central focus involving proximal vessels or bile ducts of a liver lobe |
P3 | Central focus with involvement of hilar (“pulmonary pedicle”) bile ducts or vessels of both lobes of the liver and/or involvement of two hepatic veins |
P4 | Any focus with spread along the hilar vessels and inferior vena cava (body vein entering the right atrium from caudal) and bile ducts |
N | Extrahepatic (“outside the liver“) involvement of adjacent organs (diaphragm (diaphragm), lung, pleura (lung pleura), pericardium (pericardium), heart, stomach, duodenum (duodenum), kidney, adrenal gland, Peritoneum (peritoneum), retroperitoneum (“behind the abdominal cavity”), pancreas (pancreas), regional lymph nodes, ligaments, thoracic and abdominal wall with adjacent muscles, skin, and bone). |
NX | No evaluation possible |
N0 | No evidence of involvement of adjacent organs or tissues |
N! | Involvement of adjacent organs or tissues |
M | Distant metastases (lung, CNS, spleen, kidney, peritoneum, bone, orbit (eye socket), skin, muscle, non-regional lymph nodes) |
MX | No evaluation possible |
M0 | No evidence of distant metastases |
M1 | Distant metastases |
Classification of cysts in cystic echinococcosis (CE).
Stage | Description | Activity | Therapy |
CL | unilocular lesion | active cysts |
Drug therapy
Note: In a superficially located cyst, drug therapy alone should not be used because of the increased risk of rupture due to thinning of the cyst wall. |
CE1 | Hydatidensand(“double-line-sign”) |
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CE2 | Rosette character | ||
CE3 | “water-lilly-sign”)daughter cysts | Transitional formsInvolutional stage | |
CE4 | Heterogeneous cyst contents without liquid components | inactive cysts |
Primarily inactive cysts (diagnosed as such) or cysts converted to this stage by drug therapy (CE4 and CE5) do not require treatment. Note: CE4 cysts have a potential for reactivation to CE3b cysts. |
CE5 | solid,calcified cyst |
- Primary liver cysts CL, CE 4, CE 5: observe and monitor (Wait and Watch).
- Secondary echinococcosis (spread of daughter cysts outside the parent cyst): drug therapy with a benzimidazole.