An 18-month-old, spayed female, mixed-breed dog was referred for investigat
ion of persistent hypercalcemia. After extensive diagnostic evaluation, a t
entative diagnosis of occult lymphosarcoma (LSA) was made and the dog was e
uthanized. At necropsy, infection with Heterobilharzia americana was diagno
sed. In endemic areas, schistosomiasis should be included in the differenti
al diagnosis of hypercalcemia, and a fecal examination should be performed
in every dog with a hypercalcemia of unknown origin.