THE TOPOGRAPHY, STRUCTURE AND INCIDENCE OF MINERALIZED BODIES IN THE BASAL GANGLIA OF THE BRAIN OF CYNOMOLGUS MONKEYS (MACACA-FASCICULARIS)

Whole coronal slices from 6 levels of the brain of 16 cynomolgus monke ys (8 control and 8 treated by daily gavage with a novel pharmaceutica l agent for one year) were examined histologically. Mineralized bodies were identified only in coronal sections passing through the optic ch iasma and mammillary bodies. Identical mineralized structures were pre sent in the basal ganglia of both control and treated animals. The maj ority were seen in the globus pallidus, occasionally in the putamen an d once in the nearby caudate nucleus. These structures were partially ferruginated and also partially calcified. They appeared to arise in r elation to small vessels. They are part of the naturally occurring bac kground pathology of several species of non-human primates and the inc idence in this study (3/8 control and 5/8 treated) was approximately w hat might be expected from reports in the literature. Mineralized bodi es of the basal ganglia of primates represent a spontaneous lesion wit h a characteristic distribution. They may cause confusion in interpret ation of toxicological studies if their natural occurrence is not appr eciated.