The life-span of the sparganum in humans is not exactly known, but it may survive longer than 5 years in some patients. We experienced a case infected with a sparganum that is presumed to have lived for 20 years in a patient's leg. The patient was a 60-year-old woman, and she was admitted to a hospital due to ankle pain that was aggravated on dorsiflexion. She had noticed a mass on her knee some 20 years ago, but she received no medical management for it. The mass moved into the ankle joint 3 months before the current admission, and then the aforementioned symptoms appeared. A living sparganum was recovered by surgery, and the calcified tract near the knee was proved to be the pathway along which the larva had passed.
Animals ; Female ; Histocytochemistry ; Humans ; Leg/parasitology/pathology/radiography/surgery ; Microscopy ; Middle Aged ; Sparganosis/*diagnosis/parasitology/surgery ; Sparganum/*isolation & purification