Reactivated Toxoplasmosis in a FIV-Positive Cat

An eight-year-old, FIV-positive, domestic shorthaired cat presented with weight loss and progressive neurological signs. Thoracic radiographs showed multiple pulmonary nodules and the cat was euthanased. Squash preparations of the lung lesions were made at necropsy and were cytologically consistent with carcinoma. Histologically, the cat had pulmonary and cerebellar toxoplasmosis. Tachyzoites were difficult to demonstrate in the lung lesions both histologically and cytologically. This case demonstrates the difficulties in ante-mortem diagnosis of toxoplasmosis in the cat.