A neuropathological examination was performed on a patient with parkin
sonism induced by prolonged exposure to a mixture of aliphatic hydroca
rbons, mainly n-hexane and halogenated compounds. The patient develope
d a rapid-course disease that progressed even after withdrawal from th
e toxic exposure. Pathological examination and immunohistochemical ana
lysis of the brain revealed severe and widespread dopaminergic neurona
l loss, associated with severe gliosis, in the substantia nigra, and a
lmost complete loss of tyrosine hydroxylase immunostaining in the stri
atum. No Lewy bodies were detected. Neuronal loss was also observed in
the periaqueductal gray matter, locus ceruleus, and pedunculopontine
nucleus. These changes, combined with the moderate anemia due to marro
w suppression, and the mild axonal neuropathy observed in vivo, are su
ggestive of a hydrocarbon toxic insult.