The main contraindications for PAIR are superficially located cysts (because of the risk
of rupture), cysts with multiple, thick internal septations, and cysts communicating with the biliary tree.1 The cyst in this case did have a relative contraindication to PAIR with a somewhat superficial location (which increased the risk of intra-abdominal spillage of cyst contents). The initially suspected internal Daporinad datasheet septations were actually detached cyst membranes; thus, a complication was less likely. Furthermore, the risk of PAIR seemed less in comparison with the risk of right hepatectomy. Therefore, PAIR was performed, and the aspirated cyst fluid showed hydatid sand consisting of a protoscolex with prominent hooklets (Panel B) and free-floating, Trametinib in vivo calcific hooklets (Panel C) from the degeneration of protoscolices. A diagnosis of E.granulosus was confirmed by the characteristic appearance of the protoscolex in the cyst fluid. E.granulosus is
a tapeworm infection found in areas in which dogs are used to raise livestock. Adult tapeworms develop in definitive hosts, which include dogs and other carnivores. Dogs are infected through the consumption of organs of sheep or cattle with hydatid cysts. In intermediate hosts (sheep and cattle) and humans, the larval forms penetrate the intestinal mucosa and enter the portal circulation, through which they travel to the liver and form hydatid cysts. Humans
acquire the infection through the consumption of vegetables contaminated by dog feces containing parasite eggs. Most individuals with hydatid liver cysts are asymptomatic. As the cyst enlarges, they may develop a fever, pain, tender hepatomegaly, and eosinophilia. The diagnosis relies on epidemiological data, clinical manifestations, radiological imaging, and serological tests. However, the detection of protoscolices or hooklets in cyst fluid, as in this case, is diagnostic.2 Daughter cysts develop from the inner germinal layer of hydatid cysts, as do cystic second structures called brood capsules. New larvae, which are called protoscolices, develop in large numbers within the brood capsule. Protoscolices bud off from the cyst wall and have the potential to form other cysts or to develop into adult tapeworms if they are ingested by a host (usually a dog). Surgery by which the cyst is removed without leakage of the cyst contents is the preferred definitive treatment. Cyst leakage during removal can cause fatal anaphylactic reactions, and because of this complication, percutaneous aspiration of these cysts has been contraindicated. However, in expert hands with the use of concomitant antihelminthic therapy, percutaneous aspiration for both diagnosis and therapy has been shown to be safe.3 PAIR is a procedure that can be performed safely with long-term control of echinococcal cysts.