This is the first description of human coenurus infection in Canada. The patient, a 38-year-old Caucasian woman, suffered severe and incapacitating symptoms, including recurrent rash, pyrexia, night sweats and lymphadenopathy, that were suspicious of a lymphoma, possibly Hodgkin's disease. She received several trials of chemotherapy over a 3-year period which controlled her symptoms, but only during the treatment periods. The appearance of a hemorrhagic mass in the left breast led to the surgical removal of bladder-like cysts. The patient's symptoms have not recurred since the cysts were excised. These have been identified as larvae of Taenia serialis.