Cysticercosis refers to infection with the larval stage of the pork tapeworm Taenia solium. There is a frequent misconception that cysticercosis is acquired by eating pork; this is not the case. Human ingestion of pork containing larval cysts of T solium leads to taeniasis, a localized human intestinal adult tapeworm infection. Humans usually acquire cysticercosis via fecal-oral transmission of T solium eggs from tapeworm carriers via contaminated food or water. Once in the small intestine, the ingested eggs hatch and penetrate the mucosa. The larvae (oncospheres) then spread hematogenously throughout the body and encyst in various locations. The most frequently affected sites are skeletal muscle, subcutaneous tissue, the central nervous system (CNS), and ocular structures. Involvement of the heart, lungs, kidneys, liver, pancreas, and peritoneum have also been reported.

Cysticercosis is endemic to Mexico and Latin America, Eastern Europe, sub-Saharan Africa, Indonesia, China, and southeastern Asia. The World Health Organization (WHO) has included cysticercosis as one of the neglected tropical diseases. The incidence of this important parasitic disease is rising in the United States, especially in California and other states with a large immigrant population. 

Clinical manifestations can begin months to years after acquisition. Subcutaneous cysticercosis manifests as multiple freely mobile nodules that rise years to decades after infestation. Its primary significance is as an indicator of possible neurocysticercosis, which will be present in around half of cases. Cysticerci may also invade skeletal muscle, giving rise to myositis (fever, myalgias, eosinophilia) and sometimes pseudohypertrophy. Intraocular cysticercosis may lead to vision loss.