Granular cell tumor of the canine central nervous system: Two cases

Although pure granular cell tumors have been reported in various sites in t he dog, only one tumor has been reported in the central nervous system. Two dogs presented with neurologic signs had brain lesions detected by magneti c resonance imaging in the area of the olfactory bulbs and frontal cortex. In both dogs, a clinical diagnosis of a granular cell tumor was made from t issues obtained from stereotactic biopsies guided by computed tomography. S urgical removal of the tumors was followed by histopathologic, ultrastructu ral, and immunocytochemical characterization. Although not conclusive, thes e studies indicated that the granular cells were not of leucocyte origin bu t may have been derived from the meninges. One dog died 12 months after sur gery, and the other was alive 4 months later.