Neuronal ceroid-lipofuscinosis and hydrocephalus in a chihuahua.

A two-year-old, female chihuahua presented with a six-month history of visual dysfunction. Computed tomography revealed dilation of the lateral ventricles in the central nervous system (CNS). The dog was tentatively diagnosed as having hydrocephalus and a month later was euthanased at the owner's request. The skull was expanded and dome-like in shape and an open fontanelle was observed on postmortem examination. Histologically, swollen neurons possessing yellowish pigment granules in the cytoplasm were observed throughout the CNS. These storage materials stained positively with periodic acid Schiff, Schmorl method for lipofuscin and oil red O for lipid, and showed autofluorescence under fluorescence microscopy. Ultrastructurally, the storage materials consisted of dense lamellar structures. This case was unique in having ceroid-lipofuscinosis in association with hydrocephalus.