Parkinsonian syndrome and central nervous system lymphoma involving the substantia nigra. A case report.

The clinical history and postmortem neuropathologic findings of a case of cerebral lymphoma revealed by a typical parkinsonian syndrome are reported. The clinical symptoms initially improved with dopa therapy. The tumor was classified as a diffuse, non-cleaved, large-cell lymphoma of B-cell origin producing monoclonal lambda light chains. The substantia nigra was infiltrated by the tumor and showed neuronal loss and extraneuronal pigment. The most striking histological feature was the presence of neuronophagic-like nodules composed of lymphomatous cells both in the locus niger and in the left thalamus. No tumoral mass effect and no histological stigmata of other etiologies of parkinsonian syndromes were observed. A hypothesis is that the neuronophagic-like nodules may reflect a neuronotoxic activity of the lymphoma and may be considered at the origin of parkinsonism.