NOVEL BRAIN-STEM SYNDROME-ASSOCIATED WITH PROSTATE CARCINOMA

Two patients successfully treated for prostatic cancer developed a pro gressive neurologic syndrome beginning with loss of voluntary horizont al eye movements followed by severe, persistent muscle spasms of the f ace, jaw, and pharynx. Both had mild gait unsteadiness, and one exhibi ted facial and abdominal myoclonus. Extensive diagnostic studies, incl uding MRIs of the brainstem (with and without contrast), were normal. CSF examination showed mild pleocytosis and elevated IgG. Quantitative eye movement recordings documented selective involvement of voluntary horizontal saccades with sparing of horizontal slow eye movements. Ne ither patient had antineuronal antibodies in the blood. Postmortem exa mination revealed perivascular chronic inflammatory cells and microgli al infiltration of the pons and medulla. One patient also had perivasc ular infiltrates in both mesial temporal lobes. Neuronal loss was loca lized to the pontine tegmentum, the medullary sensory nuclei, and the cerebellum. Brainstem motor nuclei were preserved. The clinical and pa thologic findings suggest an autoimmune process (probably paraneoplast ic) with selective damage to a subpopulation of brainstem neurons crit ical for horizontal eye movements and recurrent inhibition of bulbar n uclei.